Clock extration experiment based on the injection mode-locking laser is conducted. 40 GHz optical clock pulses are extracted from 40 Gb/s pseudo-random codes using injection mode-locked fiber laser. In the experiment, the injection signals pass through a Mach-Zehnder (M-Z) interferometer before going into ring cavity, so that the clock component of the injection signals increases relatively and it is beneficial to clock recovery. 10 GHz clock signal with perfect waveform from 10 Gb/s pseudo-random code, and then 40 GHz clock signal is extracted is firstly obtained from 40 Gb/s pseudo-random code after multiplexing.