A compared experiment of PM2.5 mass concentration automatic and manual sampling methods was carried out in Shangdianzi Atmospheric Background Station in Beijing from September to October in 2013 by using ray automatic observation instruments and filter-based sampling equipment. The results showed that there is good consistency and significant linear relationship between the observation data of the two methods; when PM2.5 mass concentration is lower than 35 μg·m-3 or higher than 250 μg·m-3, the deviation between the two methods is larger than other circumstances; along with the increase of PM2.5 mass concentration, the deviation of two methods increased gradually. The linear regression equation’s slope, intercept and correlation coefficient between the two methods all reach the relevant requirements of the People’s Republic of China State Environmental Protection Standard of HJ 653-2013. For all observation data, greater than 10 μg·m-3 and the range data of 10～150 μg·m-3, a correct regression equation is established respectively, and also according to the different air back trajectories conditions correct equations are established. The correction effects shows that the established equati within the rae data of 10～150 μg·m-3 is the best one.