The invention discloses an Internet of Things-based online payment system, which comprises an electronic label, a scanning module, a detection module, a positioning module, a microprocessor, a wireless communication module, a cloud server, a network database, a payment terminal and an online payment system. Through the system structure design of the detection module, the positioning module, the microprocessor, the cloud server, the network database, the payment terminal and the online payment system, real-time detection and positioning on products are realized, the online payment transaction success rate is improved, change in a consumption pattern is facilitated, and the whole system is simple in structure and strong in operability.