In visible light communication systems, if there is a problem with the pulse signal, it can cause signal distortion and inter symbol interference, seriously affecting the communication quality of the optical communication system. The traditional differential pulse position modulation method does not fully consider the impact of transmission time slots and channel characteristics on pulse position, resulting in errors and performance degradation during demodulation. Therefore, a research method for visible light communication differential pulse position modulation considering transmission time slots is proposed. Based on the visible light communication model, select the diffuse reflection transmission type in the link to obtain the pulse signal response relationship of the communication system. Based on the response relationship, determine the influencing factors of pulse delay, benchmark the frequency relationship between pulse delay and transmission time slot in the link, refer to the upper and lower boundary theory, and calculate the boundary range of differential pulse position modulation. Based on the modulation boundary and considering the channel pulse transmission time slot, determine the differential pulse position modulation equation, and design the differential pulse position modulation method for visible light communication. The experimental results show that when the pulse delay occurs in different transmission paths in the visible light communication system, the proposed method can guarantee a lower bandwidth power index, stably realize the pulse modulation of the communication system, and thus reduce the transmission bit error rate in the path.