Abstract: In order to study the effect of the cross talk on synchronization and decoding,a multichannel chaotic optical communication system was established based on vertical-cavity surface-emitting lasers(VCSELs).Based on the corresponding rate equations,similarity index was used to evaluate the synchronization performance,and 2.5Gbit/s message coding/decoding of chaotic masking method was numerically analyzed.The results show that the system can get better synchronization quality with less relative injection strength and more channel interval.The synchronization performance of dual-channel system decreases obviously compared with master-slave single channel system,and changes little when the channel number increases.The signals can be correctly recovered when the synchronization is good enough.