The invention discloses an automatic radar T / R (Transmitter / Receiver) assembly testing system and a method thereof. The main idea is: a radar T / R testing hardware platform is built, a vector network analyzer is initialized, an address, a parameter flag bit, a clock state, a channel label, a phase shifter state, a starting frequency, a stopping frequency, a scanning point number, a general testing state number, a storage file title character string, a parameter name character string, a file name character string and a file storage path character string are set, a port transmission coefficient is further built on the vector network analyzer, and a parallel port control clock of the radar T / R assembly is loaded; and then, phase data, gain data and standing-wave ratio data of the radar T / R assembly in a phase shifting state and in a degradation state are acquired respectively, the data are then processed, and the standing-wave ratio, 0-state phase, 0-state degradation, 0-state consistency phase and phase shifting precision of the radar T / R assembly in the phase shifting state and in the degradation state at a frequency point are acquired respectively, and storage by an automatic storage module is then carried out.