Nonlinearity is an important factor limiting the transmission performance of visible light communication (VLC) systems. Although orthogonal frequency division multiplexing (OFDM) technology can effectively improve the spectral efficiency of VLC, it also makes systems more sensible to nonlinearity due to its high peak-to-average power ratio. This paper proposes a post distortion method based on long short term memory(LSTM) network, which takes the local correlation of signals into account and can effectively compensate linear and nonlinear transmission impairments in VLC systems. In the case of line-of-sight transmission, compared with the post-distortion based on linear recursive least square, simulation results show that Volterra series and memory polynomials, the post distortion method based on LSTM not only can improve the performance of error vector magnitude, but also can increase signal bias voltage and dynamic range and decrease the demand for signal and noise ratio by about 4 dB with the same bit error rate.