In order to reduce the effect of multiaccess interference(MAI) on the performance of optical code division multiplexing access(OCDMA) communication systems,a new kind of parallel interference cancellation(PIC) technology based on group information used in two dimensional OCDMA communication systems with MPC/OOC is presented.Considering the effects of MAI,avalanche potodiode(APD) noise,and thermal noise,the performance of this proposed OCDMA communication systems with MPC/OOC is analyzed in detail.The results show that this proposed PIC technology with group information can effectively reduce the MAI,and when the received optical power is lager enough,the MAI in the two-dimensional OCDMA communication systems can be reduced completely.