By the means of three-dimension ray tracing method, the channel impulse response under the nonempty indoor visible light transmission environment and the root-mean-square (RMS) delay spread when light source locates in different positions of the ceiling are estimated. Based on this, the finite state Markov chain is used to model the indoor visible light fading channel, and the distribution of the non-empty indoor visible light channel impulse response is obtained. The results demonstrate that random distribution reflector imposes greater effects on the channel impulse response in the non- line of sight (NLOS) transmission environment than that in the line of sight (LOS) situation. Besides, the RMS delay spread is obvious when the light source locates at the corner of the ceiling instead of other positions, which means that the multipath effect is more obvious at this place.