The invention discloses a mobile internet payment-based self-service shopping system and method of a supermarket, and solves the problems in customer queuing for payment during peak shopping hours, theft prevention in self-service shopping, rights protection of purchased commodities by consumers and overtime accurate sales existent in the supermarket. The self-service shopping system comprises a mobile phone self-service shopping application, a cloud server and an intelligent weighing device. The mobile phone self-service shopping application is used for identifying and recording the commodities and generating order barcodes that contain prices and weights of the purchased commodities; the cloud server comprises a commodity information library and is used for obtaining information such as the prices, the weights and the like of the commodities; the intelligent weighing device is used for comparing the weights, obtained by scanning the order barcodes, of the commodities purchased by the consumers with actual weights of the commodities, and giving an alarm when difference occurs; meanwhile, the system records shopping records of the consumers, and the shopping records can serve as rights protection evidences when a rights protection event occurs; and the supermarket can perform big data analysis through shopping data to make an accurate sales plan.