Joint punishment for dishonesty has obvious administrative, industrial, social and market characteristics. The legal nature of the cooperative memorandum of joint punishment for dishonesty is mainly defined as a normative document or internal administrative agreement, but both definitions are inaccurate; the legal nature of the memorandum of joint punishment for dishonesty should be an administrative agreement in a broad sense. At the same time, it is also an important manifestation of administrative assistance in the implementation of joint punishment for dishonesty in China. There are two problems in the field of formal legitimacy of joint punishment for dishonesty, namely, the form of joint punishment has not been recognized by the law, and the cooperative memorandum of joint punishment for dishonesty does not have an authorized function. In order to solve these two problems, it is necessary to strengthen social credit legislation and confirm the measures of joint punishment for dishonesty in a statutory form; at the same time, we should also strengthen the construction of legal authorization systems to ensure that pulishment measures are based on law.