Today,the Silicon photomultiplier(SiPM),also known as Multi-Pixel Photon Counter(MPPC),has attracted much attention in recent years due to its high photon detection efficiency(PDE),good resolution for single photon detection,insensitivity to magnetic field,low operating voltage,compactness and convenience for integration,and has been an alternative to PMT in high energy physics,astrophysics and PET etc [1].Thereinto,the Photon-Number-Resolving capability(PNR)is very important for applications in quantum computing[1-3],communications[4],characterizing quantum light sources [5-6] and interferometry[7].Many efforts have been focus on improving the structure of the MPPC to enhance the PNR of MPPC [1,8-10].However,few literatures have been focus on the measuring method of the PNR of MPPC.Ref [11] proposed that the PNR capability can be improved by shortening the avalanche pulses of the MPPC using reflectometry based circuit.This method has effect on long recovery time MPPC but little effect on small pixel MPPC because of the short avalanche pulses itself.Ref [12] demonstrated a high-speed photon-number resolving detector based on a sinusoidally gated multi-pixel photon counter(MPPC).The gated MPPC can identify the photon numbers of the incident pulses with a repetition frequency of 50 MHz,but only 7.22 photons per pulse can be resolved before saturation at room temperature.Ref [13] demonstrated that photon number can be resolved at 1 GHz count rate by using a multi-pixel photon counter(MPPC)and performing baseline correction algorithm,while smaller than 2.6 photons can be clearly detected per optical pulse.Here,we proposed a method of improving the PNR capability of MPPC by obtaining the statistical histogram of the waveform integral values(i.e.areas)of the avalanche pulses.Up to 47 photon equivalent peaks can be distinguished in the Photon-Number-Resolving(PNR)spectrum with a repetition frequency of 80 MHz,which is the largest reported number obtained at room temperature as far as we know.