A remote control pit 1-channel drilling rig based on PLC is composed of a host machine, a pump station, an automatic loading and unloading device for drill pipes and a PLC control system. The main machine structure consists of a feed device, an upper gyrator, a lower gyrator, a gripper and a frame. The feeding device comprises an upper oil cylinder, a lower oil cylinder, a carriage, an upper carriage and a lower carriage. The oil cylinder adopts a double-rod structure, which is divided into an upper oil cylinder and a lower oil cylinder. The reciprocating motion of the cylinder body drives the upper carriage and the lower carriage to move along the carriage guide rail. The upper gyrator and the lower gyrator are composed of motor, gear reducer and rubber cylinder type hydraulic chuck. The motor is an inclined axis variable plunger motor, and the chuck is a rubber cylinder structure with oil pressure clamping and spring loosening. The upper gyrator and the lower gyrator are respectively installed on the upper carriage and the lower carriage of the feeding device by means of slot type connection. The upper carriage and the lower carriage are slidably connected with the carriage guide rail, and the upper oil cylinder and the lower oil cylinder of the feeding device respectively drive the reciprocating movement along the carriage guide rail. The upper gyrator is used for feeding or pulling up the drilling tool, and the rotation of the lower gyrator is used for loading and unloading the drilling rod and unloading. The gripper is fixed at the front end of the machine body of the feeding device, and is used to grip the drilling tool in the hole and mechanically screw and unscrew the drill pipe in cooperation with the gyrator. The frame is used to fix the main engine, install the feeding device and adjust the inclination of the machine body, and is composed of a base, a front support oil cylinder, an auxiliary support oil cylinder and a rear support oil cylinder. The frame base is connected with the carriage through the front support oil cylinder, the auxiliary support oil cylinder and the rear support oil cylinder, and the support oil cylinder is adjusted to meet the needs of drilling at different angles. The pump station adopts YZL type (vertical) hydraulic pump station. The motor drives the pump station to work. The direction, pressure and flow of the driving device are adjusted and controlled through the integrated block and hydraulic valve to provide power source for the drilling rig. The automatic loading and unloading device of drill pipe is composed of drill pipe box, conveying device, grabbing crank and lifting device. The drill pipe box is composed of partition plate, lifting device and pipe outlet. The drill pipe box is fixed on the side of the fuselage by welding, and a drill pipe placement cavity is arranged inside, and adjacent drill pipe placement cavities are separated by partitions, and a lifting device is arranged in the drill pipe box, which can be raised and generate a certain angle. The rod outlet is provided with a side plate, which is riveted on the drill rod box. The conveying device is fixed on the drill pipe box by welding, and a cylindrical pulley is installed inside it to convey the drill pipe to the designated position. The end of the grab crank is welded with a manipulator, and the other end is fixed on the motor through a key connection to realize the rotation of the grab crank within the range of °. The end of the manipulator is a sleeve structure, and a limiting ring is arranged at the bottom end of each sleeve for the expansion and contraction of the manipulator. The lifting device is fixed on the transmission device through the connecting rod, and its interior is composed of a closed cam structure and a manipulator. The upward lifting action of the manipulator can be realized through the rotation of the closed cam structure. PLC control system to PLC as the core, by the input and output link. PLC control system can be divided into manual control and automatic control of two modes. The input links of PLC control system mainly include: monitoring the drill pipe position in the drill pipe box 5, monitoring whether water reaches the drill bit position, monitoring the position of the gyrator, monitoring the forward distance of the gyrator, setting the length of the drill pipe, querying the drilling distance and displaying the error alarm type. The output links of PLC control system include: frame adjustment, drilling rig work, drill pipe loading and unloading, and error alarm. Frame adjustment: the front support oil cylinder rises/falls, the auxiliary support oil cylinder rises/falls, and the rear support oil cylinder rises/falls; drilling rig work: water inlet valve opens/closes, gripper opens/closes, upper carriage advances/retreats, lower carriage advances/retreats, upper gyrator feeds/pulls, lower gyrator rotates/stops, upper chuck clamps/loosens, lower chuck clamps/loosens; drill rod loading and unloading: side plate on/off, lifting device up/down, transfer device on/off, lifting device up/down, grab crank rotation/stop, manipulator grab/release, manipulator extension/homing;