Integrated Sensing and Communication is a promising technology that can solve spectrum congestion in future wireless networks. As a typical application of the 6G ISAC system, target sensing is the basis of other sensing tasks. In this paper, we propose an effective method to process the echo signals due to the two-dimensional structure of OFDM. We derive a cyclic cross-correlation-based method to obtain the Range Doppler Mapping and estimate the target’s parameters. Furthermore, to get clearer targets on the RDM, we employ an improved cruciform CFAR detection. Simulation results prove that the signal processing method we adopt is computationally faster and has better performance.