This paper proposes a model of short light pulse photon number resolution for the multi-pixel photon counter(MPPC) based on the photoelectric characteri stics and operating principle of the MPPC.The analytical expressions of two models, which are based on the convolution of the functions of the Poisson distribution and the Gaussian distribution,are derived.One does not take optical crosstalk int o account while the other does.The photon number resolution spectrum of the lat ter model is in accordance with the experimental results,which shows that the devia tion of spectrum from ideal case is mainly caused by the optical crosstalk effect.Th is model can infer the average photon number of the incident light pulse accurately and judge whether the input photon number statistical distribution is the expected o ne rapidly.It can also be extended to other cases of photon number statistical dis tribution. This model has significance not only on further understanding the photoelectric characteristics and mechanisms of MPPC,guiding the design and optimization of MPPC,but also on promoting the application of MPPC in the field of low-level-light detection,such as measurement of the photon statistical distr ibution and characterization of the single photon source.