Abstract: This article analyzed hourly PM（2.5）data of 81 na tional air quality monitoring sites of Beijing,Tianjin and Hebei region in 2013,and explored the dynamic changes of PM（2.5）from seasons and months.The results showed that PM（2.5）concentrations in Beijing,Tianjin and Hebei region from high to low of season were Winter,Fall,Summer,Spring.Regional distribution are Hebei,Tianjin,Beijing,the result was closed to heating in winter,burning of fossil fuels and coal;In 2013,the average monthly change of PM（2.5）was consistent,but the January,February and December was relatively high,then gradually decline in March.