Butler matrix is a test system that simulates between the base station and the mobile terminal, which simulates the beam angle of the antenna array through a fixed phase combination between channels. It can transmit the signal from any of multiple input ports to any of the multiple output ports, with high phase accuracy, amplitude balance, low insertion loss and high port-to-port isolation. The Butler matrix is suitable for multiple frequency bands and has a variety of input and output forms, including 4 in 4 out, 8 in 8 out, 16 in 8 out, 32 in 32 out and 64 in 32 out. This system greatly facilitates the testing of equipment manufacturers and saves a lot of time compared with traditional testing.