Abstract: Pulse compression is an effective means for increasing the output peak power of microwave sources, the coupling coefficient characterizes the coupling strength between the input waveguide and the storage cavity. In order to change the coupling coefficient in different stages of active SLED compression experiment, a pulse compressor system with adjustable coupling coefficient was designed by the adapter function of H-T waveguide junction and shorting piston. The adjustment capability of the waveguide H-T was analyzed based on the scattering matrix theory. The passive SLED pulse compression experiment was carried out by single storage cavity when the 3dB coupler was replaced by a high power waveguide circulator. The experiment results show that the adjustment capability of the waveguide junction agrees with that of the theoretical analysis.