The invention provides a solar simulator used for a sun sensor. The solar simulator comprises a mounting bracket, a posture adjusting device, an LED light source module and a control system; the mounting bracket is detachably mounted on the sun sensor, and the posture adjusting device is arranged on the mounting bracket; and the LED light source module is arranged on the posture adjusting device,and the control system is electrically connected with the posture adjusting device and the LED light source module, wherein light rays emitted by the LED light source module are aligned with a probe of the sun sensor. The solar simulator used for the sun sensor satisfies conducting of a field test on the solar sensor after being loaded with a satellite on the ground.