The invention discloses a detection device of an on-orbit radiation risk of a spacecraft. The detection device comprises a detector shell and seven built-in detection unit groups. Each detection unitgroup consists of a temperature sensor and a total dose detector; the shell part right above one detection unit group is opened to ensure detection without shielding limiting of the shell; the anotherdetection unit group uses the spacecraft shell as a shielding layer for detection and the other five detection unit groups are provided with metal shielding layers with different thicknesses to detect different space radiation effects. Each detection unit group is arranged on the intermediate circuit board for collecting the temperature and the total dose. The detection device has characteristicsof simple structure, small size, light weight, low power consumption and the like; risks of different space radiation effects such as a surface charge-discharge effect, a total dose effect, a singleparticle effect, a displacement damage effect, an internal electrification effect and the like can be determined.