Abstract: According to the application requirements of microwave millimeter wave kilowatt level solidstate power amplifier, a variant 4-port E-Plane Waveguide T-type combiner with isolation port is designed. The design results are that the return loss of input and output ports is less than -20 dB, the isolation is better than -20 dB, the signal insertion loss in frequency band is less than 0.07 dB, and the amplitude imbalance is less than 0.04 dB at 34 ~36 GHz, the phase difference is (180 ± 0.2)°. In the measurement process, 8 channel back-to-back test is adopted, the loss is less than 0.6 dB, and the combining efficiency of waveguide network reaches 90%. While the structure is applied to solid-state microwave power amplifier, at 34 ~36 GHz, the measured saturated output power is 1 050 ~1 200 W, the linear gain is 50 ~52 dB, and the drain efficiency is 22% ~25%.