Abstract: This article proposes an hourly modeling method of PV power generation system. Solar irradiation model,PV module model,inverter model,DC terminal partial line loss model,AC terminal partial line loss model,transformer loss model and various link loss models are established,and coupled these models together to obtain different hourly solar irradiation received by PV array with different type of PV bracket,the hourly power generation of the PV array,the hourly loss of the PV power generation system,and the hourly grid-connected power of the PV power generation system. With the same meteorological data,using this model and PVsyst to simulate the grid-connected PV power generation system with a capacity of 24.3 kW in Sanya,Kunming,Nanjing,Beijing and Harbin. The maximum and minimum deviation of amount of solar irradiation received by PV array is 1.01% and 0.21%,respectively. The grid-connected power maximum deviation is up to 0.49% and the minimum is 0.04%. The PR maximum deviation is up to 0.5% and the minimum is 0.2%. The various loss deviations are very small.Compared with PVsyst,the simulation result has a small deviation and high accuracy,which can be used for refine simulation of PV power generation system.