For solve the problems of large volume, high cost, complex operation and other issues of the current electric field detectors, a miniaturization atmospheric electric field monitor system is developed. The system uses a capacitance as a sensor sensing unit, a twophase fourwire stepper motor as a sensor detects unit, and STC12LE2052AD SCM (Single Chip Microcomputer) with a builtin A/D converter to collect data; in this way, the circuit is simplified. Combining the Bluetooth module and the data acquisition system can realize the realtime display function, and the data can be seen in the host computer. The hardware circuit includes the amplification filter circuit, A/D convert circuit, and data acquisition and processing circuit. By MATLAB simulation and C language programming, the experimental results show that the system can meet the requirements of actual measurements, with the measuring error less than 4%.