Aiming at the problem that the multi-pixel photon counter (MPPC) is susceptible to background light interference and the synchronization clock signal is difficult to extract in the process of signal recovery, an improved synchronous communication method of photon counting based on MPPC is proposed. First, the MPPC is use to complete the photoelectric conversion, the mean value (MV), Anscombe root (AR) transformation and maximum likelihood (ML) optimal threshold detection algorithm of the Poisson distribution model are used to pre-judge the electrical pulse. Second, the gated periodic clock with different phases is generated, which is used as the enabling signal to count the sum of pulse counts, and the best slot-dependent synchronous clock is determined by searching its maximum value. Finally, the relative size of pulse count per bit and count threshold is compared to determine bit information. In order to verify the effectiveness of the method, a wireless optical communication system based on MPPC is built. The experimental results show that under the conditions of a wavelength of 520 nm, a communication rate of 2 Mbit/s, a sampling frequency of 200 MHz and a bit error rate of 3.8×10^-3, the sensitivity of the improved PCPB-MV, PCPB-AR, and PCPB-ML detection algorithms is 3.0 dB, 3.2 dB, and 3.8 dB higher than that of the traditional detection algorithms, respectively.