Selling medical masks without obtaining the business qualification certificate of medical devices. It also constitutes the crime of illegal business operation. Legal basis: Article 225 of the Criminal Law violates state regulations and commits one of the following illegal business operations, disrupting the market order, and if the circumstances are serious, he shall be sentenced to fixed-term imprisonment of not more than five years or criminal detention, and shall also, or shall only, be fined not less than one time but not more than five times the illegal income; If the circumstances are especially serious, he shall be sentenced to fixed-term imprisonment of not less than five years, and shall also be fined not less than one time but not more than five times his illegal income or his property shall be confiscated: 1. Without permission, dealing in monopoly commodities or other commodities whose operation is restricted by laws and administrative regulations;

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;

3. Without the approval of the relevant competent departments of the state, illegally engaging in securities, futures and insurance business, or illegally engaging in fund payment and settlement business;

4. Other illegal business operations that seriously disrupt the market order.