The invention relates to an electromagnetic and thermal stress complex environmental sensitivity testing method for a microprocessor. An RF interference signal source (1), a power amplifier (2), a coupling capacitor (3), a power supply distribution network (4), a tested microprocessor (5), a PCB (6), a thermostatic heating tank (7), a DC power supply (8) and an oscilloscope (9) are included. The method also provides a capacity coupling injection interference based method for testing the electromagnetic and thermal stress complex environmental sensitivity of a microprocessor. The system is easy to build, low in cost and quick and convenient in testing, and solves the problem that the testing of the electromagnetic and thermal stress complex sensitivity of the microprocessor is difficult; meanwhile, the testing method is simple, the operating process is definite, the electromagnetic sensitivity of the microprocessor at different work environment temperatures can be accurately tested within the whole frequency band ranging from 150 KHz to 1 GHz, and sample testing can be carried out at an appointed operating temperature or a certain frequency point.