An angle measurement system of a two-channel rotary transformer for spaceborne equipment is designed. For the purpose of obtaining high precision motor rotation angle value, the principle, error analysis, data combination algorithm and the software and hardware design of the angle measurement system are studied, and FPGA is used to detect and calculate the angular displacement of the stepping motor. In order to verify the accuracy of the designed two-channel angle measurement system, a Heidenhain photoelectric encoder with higher resolution is used to collect the data at the same time. By comparing the two data, it is shown that the error of the designed angle measurement system is within 30 ″, which meets the design accuracy requriements.