Abstract: ‍ ‍The integrated radar and communication system （IRCS） can improve the availability， reliability and electromagnetic compatibility of multi-system platforms. Therefore， IRCS has become a hot research topic in the cross field of radar and communication. The orthogonal frequency division multiplexing （OFDM） signal has good communication capability and its ambiguity function has low sidelobes， thus it has received extensive attention in IRCS. In OFDM-IRCS， the co-channel interference seriously affects the performance of radar detection during networking. Aiming to address this problem， the co-channel interference for IRCS is analyzed from the aspects of signal-to-interference ratio （SIR） and the SIR is derived. Then， combining the interleave division multiple access and interference reconstruction in OFDM， a co-channel interference suppression algorithm for IRCS based on OFDM-IDMA is proposed. The proposed algorithm distinguishes the signals of different integrated nodes via different interleaving patterns， and realizes the interference suppression through the interference cancellation algorithm based on interference reconstruction. The simulation results show that the proposed algorithm effectively suppresses IRCS co-channel interference and improves the detection performance.