The device is divided into data acquisition terminal, operation processing terminal and user terminal. On the hardware of the data acquisition terminal, based on the portable application standard design, it supports the independent power supply of lithium battery and USB power supply, and the power supply mode can be automatically switched; on the software, the RT-Thread operating system is used for task scheduling, which has high real-time performance. On the computing processing side, a computing processing terminal is built based on the strawberry pie, which has the functions of front-end interface display, background TCP server and ventilation rate calculation. Using multi-thread technology, the front and back data display, processing business logic separation, improve the efficiency of the software. On the user side, based on Java technology, an APP that can obtain data from the strawberry pie is developed to realize the data interaction between the data acquisition device, the computing processing terminal and the user side. Summary of works: Objective: To improve the traditional test method of indoor ventilation rate, and realize the high precision and fast measurement of indoor ventilation rate. Methods :( 1) Using PM2.5 as a tracer, a numerical algorithm was designed to solve the room air exchange rate. (2) With the help of sensors and embedded technology, a wireless measuring device for measuring room air exchange rate is developed. The device includes three modules: data acquisition terminal, operation processing terminal and user terminal. 3. Results: Two ordinary rooms were selected for the air exchange rate test. The air volume of room 1 was about 22.5 m3, and the air volume of room 2 was about 18.8 m3. Based on the stable experimental results, the air exchange rate of room 1 is calculated to be about 0.36 h-1, and the air exchange rate of room 2 is about 0.16 h-1. The verification test is carried out using the internationally recommended CO2 attenuation method. The test results show that the air exchange rate of room 1 is about 0.38 h-1, and the air exchange rate of room 2 is about 0.17 h-1. Compared with the results of the particle attenuation method, the relative error of the room 50.00g method is 10.5%, and the relative error of the room 2 is 5.9%, but the test time based on the particle attenuation method is only half of the CO2 attenuation method. Conclusion: The system can not only obtain the same high-precision ventilation rate results, but also has a great advantage of time and cost, and can realize the rapid measurement of indoor ventilation rate.