To meet the needs of secure communications, a scheme of chaotic synchronization based on the two unidirectionally coupled semiconductor ring lasers (SRL) is proposed. The wave form, power spectrum and self (cross) correlation diagrams under several parameters are obtained by numerical simulation, and the effect of injection parameters on chaotic synchronization performance is studied. The results show that the time-delay signatures (TDS) of chaotic signals are obvious when the master SRL is subjected to the optical cross-feedback, which is not conducive to the secure communication system. After introducing optical self-feedback in the master SRL, the TDS is well suppressed, and the quality of chaotic signals is significantly improved. The chaotic signal with low TDS is injected into the slave laser to achieve chaos synchronization. Under the fixed frequency detuning, it is found that the synchronization coefficient can be significantly increased by increasing the injection coefficient. In addition, by drawing a two-dimensional space map, the high-quality chaotic synchronization region with a synchronization coefficient above 0.9 can be determined.