In order to solve the problem of peak to average power ratio (PAPR) in DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM) visible light communicati on (VLC) system,a joint PAPR reduction algorithm based on combining clipping and normalized μ-la w companding is proposed.Firstly,some big peak signal in the time-domain is clipped by amplit ude limiting to reduce the amplitude of the signal,and then the clipped signal is further processed b y a normalized μ-law companding transform.With this way,the PAPR of DCO-OFDM signal can be effecti vely reduced. Experimental simulation result shows that the value of complementary accumulativ e function is 10－3 when 16QAM modulation is adopted,compared with the algorithm combined amplitude limiting with traditional μ-law companding transform,the PAPR of the combined algorithm dec reases by about 2.206 dB.