A multi physics co simulation method is employed for analyzing the microwave response of a Schottky diode with model number HSMS 282c. Results show the device’s power dissipation with package is 87 percentages higher than that without package. The average power dissipation in the diode under the microwave excitation of different frequencies is also studied. It shows there is a maximum power dissipation of the diode at about 35 GHz. When the diode works above 32 GHz, its power dissipation will increase with ambient temperature rising. The obtained results have great value for the study of microwave effects in semiconductor devices.