The invention discloses a portable intelligent electric meter recharge fault detection system which comprises a detection conversion board. The detection conversion board is provided with a CPU card seat and connected with an MCU, the MCU is connected with a display screen, and recharge fault detection software and a fault diagnosis expert base are embedded into the MCU. The detection software comprises an interior and exterior identity authentication module, a parameter updating module, a wallet recharge module and an information rewriting module. A menu interface of the detection software comprises a fault diagnosis interface. Fault diagnosis comprises the steps of data processing, wherein message monitoring and receiving, message analyzing and data storing are performed; diagnosis analyzing, wherein data obtained before and after card recharging is analyzed, and fault diagnosis expert bases are compared to analyze problems and errors; data displaying, wherein basic information, manufacturer information, meter reading information and fault information of an intelligent electric meter are displayed. According to the system, an instruction flow set of correct interaction of the intelligent electric meter and an electricity purchasing card in the recharge process is carded through a monitoring method for interactive data of the electricity purchasing card and the intelligent electric meter, and therefore a recharge fault is quickly positioned.