Pulse amplitude modulation（PAM）signal has attracted wide attention due to its simple application principle and low power consumption in the visible light communication（VLC）system. However, a high-frequency power attenuation of signals may result from the bandwidth limitation and nonlinear effects of optoelectronic devices, which reduces the effective bandwidth and system performance of signal transmission. Therefore, a PAM8-VLC system has thus been proposed based on frequency domain precompensation, which suppresses the impact of high-frequency power attenuation on signal transmission performance by performing a frequency domain precompensation on the S21 response curves of the PAM8 signals. The experimental results show that after a 3.5 m free space visible light link, the pre-compensated PAM8 signals, compared with non-pre-compensated PAM8 signals, can improve the reception sensitivity by 2 dB with an error rate lower than the hard decision forward error correction（HD-FEC）threshold, meanwhile achieving a system transmission rate as high as 1.8 Gbit/s.