Prepaid vending management system includes three main parts, key system, vending management system and marketing business application. Key system consists of key system structure and function, encryption & decryption system, etc. Vending management system includes user management, user card (power purchase card) management, vending management, meter parameter management, query management, report management, exception handling, HHU applications, and auxiliary management module and so on. While marketing business applications includes clearing account management, measuring management, meter reading accounting, accounting treatment, interface function module, etc.