Orthogonal frequency division multiplexing (OFDM) radar signal has good resolution and high spectral efficiency; and OFDM radar signal based on chaotic binary-phase coded modulation is widely favored due to its flexible structure, better pulse compression performance and strong anti-jamming capability. However, the high peak-to-average power ratio in the system makes the OFDM radar limited in practice. A selective mapping (SLM) algorithm based on chaotic particle swarm optimization (CPSO) is proposed to reduce the peak-to-average power ratio for the OFDM radar signals modulated by different chaotic binary-phase coding sequences. The experimental results show that the SLM algorithm based on CPSO has better effect in reducing the peak-to-average power ratio of OFDM radar signal than traditional SLM algorithm and basic particle swarm optimization SLM algorithm.