If the organizational relationship is shifting, the statutory "party member certification materials" are "organizational relationship introduction letters". If it is generally proved that a person is party member, you can ask the party organization where the comrade belongs to issue corresponding proof materials. If you want to know whether a comrade is party member, you can also check the party member archives of the comrade (including: application for joining the Party, certificate of completion of Party school training, and volunteer letter (complete and stamped with a new chapter).

Legal Basis: Regulations on the Work of Party Branches in China (for Trial Implementation) Article 1 In order to uphold and strengthen the overall leadership of the Party, carry forward the glorious tradition of "the branch is built on the company", implement the requirements of the Party for managing the Party and strictly administering the Party in an all-round way, comprehensively enhance the organizational power of the Party branch, strengthen its political functions, give full play to its role as a fighting fortress, and consolidate the organizational foundation of the Party's long-term governance.