This work is based on the inspiration of the protection of Qinghai thangka, in order to better protect and inherit the intangible cultural heritage and the basic rights and interests of its authors, the use of blockchain technology research and the design of key links, to achieve the Qinghai thangka original works of feature identification and extraction, the determination and design of infringing paintings. This work uploads the original painting and the suspected infringing painting in the running page, extracts different types of hash values from the picture through programming, and compares the two works to calculate the similarity of the two works, and then determines whether the suspected work constitutes infringement. At the same time, this work can accurately identify the infringing paintings of black and white, beautification, size modification and other operations. This work can not only be used for the detection of thangka in Qinghai, but also can be widely used in the detection and analysis of infringement of all kinds of original paintings, and can basically realize the copyright protection of paintings.