The invention discloses a USBKEY (universal serial bus key)-based online electric charge payment system. According to the USBKEY-based online electric charge payment system, after plugging a usbkey into a computer, a user inputs PINs (personal identification numbers) firstly and starts desktop payment application software to be connected with a server for identity authentication and communication secret key negotiation after the PINs pass, a communication secret key conforms to a one-time pad principle, and the user can maintain personal information, inquire electricity consumption information, pay charges and view historical bills and arrearage warning information through the desktop payment application software. According to electric charge practical situations in different districts, a card writer is provided for a user who needs card writing after payment and is integrated with the usbkey, and after login of the usbkey is completed, the user can perform card writing operation by invoking an interface of the card writer and can complete card writing operation with the card writer after completing electric charge payment, so that electricity is restored. The USBKEY-based online electric charge payment system integrates an enterprise E-bank, quick payment and a company integrated payment platform to achieve real-time receiving of the charges, so that electric charge transit time is shortened and risk of company's electric charge arrearages are reduced.