Abstract: Using the hourly observation data of 366 environmental quality monitoring stations in China,the variation and distribution characteristics of PM_2.5 concentration of China in 2017 were statistically analyzed.The results show that:(1) The average annual PM_2.5 concentration in 2017 is 133μg/m³,the minimum value is 10μg/m³ in Hetian,the range of maximum is from 21μg/m³ to 1266 μg/m³,and the minimum value of the PM_2.5 concentration difference is 19 μg/m³,the maximum value of the difference is 1248 μg/m³.(2) According to the annual average,the maximum and minimum of daily mean values,the spatial and temporal distribution of the difference,the areas with relatively high PM_2.5 mass concentration are in parts of North China、northeast China,and a few are in Central China.The areas of lower value are northwest,southwest and southeastern coastal areas.(3) The seasonal variation of PM_2.5 concentration is roughly winter> autumn> spring> summer;The variations of PM_2.5 concentration in Xinjiang and Tibet are largely affected by seasonal changes,the southern China and coastal areas are seldom affected by seasonal changes.