Abstract: In order to study the influence of chemistry structure of FDLC film on optical property, the fluorinated diamond-like carbon(FDLC) films were deposited on the glass substrate with the method of PECVD, and analyzed by AES, FTIR and UV-VIS. The result shows that the deposited films are typical diamond-like structure and the fluorine in the films exists in the form of C-F2 key; the content of C-F2, increases in the first period and then reduces as the temperature continuously rises in the deposition process; the sp3 content of FDLC films decreases and the sp2 content increases when the fluorine content increases; the optical band gap has a close relationship with the content of sp2 key, and the more the sp2 content is, the smaller the optical band gap will be.