The invention provides an automatic testing device and method of a phased array radar TR assembly, and relates to the technical field of electronic equipment testing. By generating a specific radio frequency signal, connection or disconnection of a radio frequency switch is controlled, the transmission path of a TR assembly radio frequency signal is carded, a power attenuator and a load are arranged inside a radio frequency switch matrix unit, finally, a testing instrument is connected with the phase array radar TR assembly automatic testing device through a testing instrument interface unit,and testing of TR assembly performance parameters is completed. By means of the phased array radar TR assembly automatic testing device and method, the detection speed of detecting performance parameters in all devices in the TR assembly is increased, the reliability and accuracy of testing performance indexes of all the devices in the TR assembly are improved, and the possibility that the testinginstrument is damaged when input power is too large is lowered.