To ensure the safety of spacecraft in orbit, the detection of real-time monitoring of the orbital space environment and obtaining the surface charge effect data are required. Based on the analysis of orbit charging environment, the mission target is determined and the scheme design based on the protential probe and the current probe is completed, including the probe design and the circuit design. This detector is a key step in the measurement of special effects in space environment, which lays a solid foundation for the measurement of more parameters of space effects.