The invention discloses a pre-purchased power controller, which is characterized in that an MCU microprocessor is arranged, the peripheral devices of the MCU microprocessor comprise a signal conditioning module, a data memory module, a clock chip, a non-contact IC card reading and writing module, a liquid crystal display module, a power supply and cutoff executing module, a cell phone communication module, an infrared communication module, a multi-way switch, an RS 485 communication interface, a pulse acquisition interface and a key module. The invention can realize automatic meter reading and power fare calculation, can give alarm or supply and cut off power according to the remaining sum of the prepaid power fare, can communicate, send alarm information by using cell phone short messages and conduct grid monitoring, can modify parameters through infrared, and has the function of accepting the non-contact IC card recharge operation.