To solve the problem of the low transmission rate of traditional differential chaos shift keying (DCSK), a multiuser orthogonal DCSK communication system is proposed. The proposed system distinguishes different information time slots by delaying different times, sending N users in per-information time slot to improve its transmission rate. Meanwhile, the orthogonal chaotic generator is used to generate two orthogonal chaotic signals to completely eliminate the intra-signal interference and improve the performance of the bit error rate (BER). In the proposed system, BER and the transmission rate can be analyzed from two aspects: the number of delay lines and the number of users. The BER formula under additive white Gaussian noise and Rayleigh fading channels is derived and simulated. Simulation results show that the system can effectively improve the performance of BER and increase the transmission rate, furthermore it has good practical value.