In order to realize high-precision time-frequency signal transmission more flexibly and conveniently, spatial link is used to replace optical fiber for proceed time-frequency transmission. This paper describes the basic principle of frequency transmission of free space optical frequency comb. In the experiment, the femtosecond optical frequency comb locked to the rubidium atomic clock is sent to the far end through a 102 m free space link, which is detected directly by a high-speed detector, and the optical frequency comb repetition data are collected by a high-precision frequency counter. The experimental results show that the system is finally realized the jitter scope of the 100 MHz repetition signal at the receiver is 3.5 mHz in 30 min, and the repetition frequency stability is 4.26×10-12/s、4.81×10-13/100 s.