The packaging of solid state microwave power devices is special, so it is necessary to use measuring fixture as the bridge in the measurement process and the conversion of the interfaces for convenience of the testing. In microwave electric parameters test of solid state microwave power devices, the measurement errors caused by measuring fixture cannot be ignored, and this paper studies the measuring fixture and calibration technology of a solid state microwave power device. In this paper, the TRL calibration method is adopted, the error correction function of the vector network analyzer is used to remove the error of measuring fixture, and thus the real performance parameters of the device are obtained. The test data show that it is feasible and effective to calibrate the measurement fixture and remove the error, so that the pure parameters can be obtained by removing the effects of the measuring fixture.