In order to realize high-speed communication between two rotating parts, a free space optical communication system suitable for double-end rotation is designed. By designing an aspheric collimator and selecting proper two-way color splitter, the optical signal can pass through the center of rotation axis, and the laser signal emitted from one rotating part can be transmitted to the light detection module in another rotating part. When the distance between the two rotating ends changes from 10 mm to 550 mm, and the relative speed changes from 10 r/min to 120 r/min, the minimum received power of the system can still meet the communication requirements, and the bit error rate is 0.