Abstract: In order to improve the light intensity scintillation effects on signals under the turbulent channel of complex traffic environment, we studied the system model of the atmospheric turbulence intensity scintillation in theory, and put forward a new kind of modulation method of free space optics(FSO), head pulse position modulation(H-PPM), aiming at the existing problem of pulse position modulation (PPM) and differential pulse?position modulation (DPIM) methods.According to the characteristics of turbulent channel, we derived the slot error rate formula of visible light communication system based on H-PPM when encoded with Reed-Solomon(RS) code or not.The results of numerical simulation show that the RS(15, 7) code can improve about 18 dB coding gain when the system bit error rate is 10^-10.Therefore, the combination of H-PPM modulation and RS coding can improve the quality of the signal and facilitate the visible light communication in complex traffic environments.