Aiming at the problem of high peak-to-average power ratio(PAPR) in asymmetrically limited optical orthogonal frequency division multiplexing(ACO-OFDM) systems, an uplink multiple access scheme that reduces PAPR is proposed, using selective mapping-sparse code division multiple access(SLM-SCMA) technology suppresses the PAPR of the ACO-OFDM system, and the performance of the ACO-OFDM system is simulated through Matlab software. The simulation results show that when the number of subcarriers N=512 and the CCDF value is 10-4, the PAPR of the ACO-OFDM system without and with SLM-SCMA technology is 11.82 dB and 7.02 dB respectively.