The frequency-locked multi-carrier source is a key element for achieving Tb/s data rate transmission. It has high frequency efficiency and its implement is simple. Therefore, it has become the topic in high-speed mass optical fiber communication system. The structure of the I/Q modulator and the operation principle for generating multi-carrier are analyzed in theory, the experimental system of frequency-locked multi-carrier source based on I/Q modulator is set up. The 15-carrier space at 12.5 GHz generation is successfully conducted. Simultaneously, the parameters affecting the performance of the muti-carrier source is analyzed by simulation. The results show that the radio frequency drive voltage, the variation of states of polarization are main factors to affect the generation of the frequency-locked multi-carrier source.