Based on the theoretical model of the synchronization system with incoherent optical feedback,the effects of the internal parameter mismatch on the synchronized characteristics and message encoding and decoding of the chaotic system have been investigated.The results show that the chaotic system with incoherent optical feedback can be realized more easily than the completely synchronized system,and has higher security than the injection locking synchronization system,When the message bit rate is 250 Mbit/s,chaos shift keying(CSK) and chaos masking(CMS) can decode the message easily in the receiver,when the bit rate increases to 2.5 Gbit/s,CSK can not decode the message and the quality of decoding message for CMS becomes bad,and finally when the frequency increases to 12.5 GHz,both CSK and CMS can not decode the message,but additive chaos modulation(ACM) can decode the message easily even at this high bit rate.