This situation depends on the relevant situation. It is illegal to help them sell if they know that they are unqualified products. It may constitute the crime of illegal business operation. According to the provisions of Article 225 of the Criminal Law of People's Republic of China (PRC), it refers to the crime of committing one of the following illegal business operations in violation of state regulations: (1) engaging in the exclusive sale of commodities or other commodities whose trading is restricted by laws and administrative regulations without permission; (2) buying and selling import and export licenses, import and export certificates of origin and other business licenses or approval documents stipulated by laws and administrative regulations; (three) without the approval of the relevant competent departments of the state, illegally engaged in securities, futures, insurance business or illegally engaged in fund settlement business; (four) engaged in other illegal business activities, disrupting the market order, and the circumstances are serious.