The present invention relates to the field of semiconductor integrated circuit manufacture, and discloses a field effect transistor (FET) microwave noise model building method. The method comprises the steps of dividing an FET electrode into four regions, that is, a gate input structure, a drain output structure, a source grounding structure and an active region electrode, simulating a transmission feature of a microwave signal in the FET electrode by using a full-wave electromagnetic field method, and acquiring an S parameter of each region; converting the active region electrode of the FET into an equivalent circuit model, respectively inputting the acquired S parameter of the gate input structure, the acquired S parameter of the drain output structure and the acquired S parameter of the source grounding structure to three connecting ports, and acquiring an FET passive electrode model; performing on-chip test on the FET, acquiring a small signal and noise test data, and acquiring a small signal parameter and a noise source of an intrinsic part of the FET through de-embedding processing according to the test data; and inputting the small signal parameter and the noise source to the FET passive electrode model according to a port correspondence, and acquiring an FET microwave noise model.