In order to solve the problem of large envelope fluctuation in the application of MCPC radar signal, this paper proposes an optimization design based on chaotic mapping and SCPSO algorithm, and makes revelant simulation analysis. PSLR of the coded signal is used as a separate evaluation basis. Combined with the random-like property of the chaotic sequence, the sequence is screened by two levels, and a group of chaotic coded sequences with lower autocorrelation function sidelobes is obtained. Considering the characteristics of MCPC signal structure, SCPSO algorithm is applied to adjust the subcarrier weight factor to optimize the PMEPR of the signal. As a result, the design can effectively reduce the signal envelope fluctuation while ensuring the excellent autocorrelation characteristics of MCPC signal.