In view of the difficulties in monitoring summer rainy season in North China, the concept of the summer potential rainy season in North China is proposed, and a new monitoring method， i.e., the speci-fic humidity subtropical high method, is established. The main monitoring results are as follows. The average start date of the summer rainy season in North China from 1961 to 2022 is 10 July, the end date is 8 August, and the rainy season lasts for 28 days. The start and end time of the rainy season in North China has no obvious long-term change trend, but the interdecadal change is significant. The summer rainy season precipitation and the comprehensive intensity index of rainy season monitored by this method in North China are very consistent with the changes in summer precipitation, which is a high positive correlation. This indicates that the monitored rainy season parameters have a good indication of the changes in summer precipitation in North China. The start and end of the summer rainy season in North China are accompanied by significant changes in atmospheric circulation. The East Asian subtropical summer monsoon at 850 hPa strengthens and weakens, and the atmospheric specific humidity in North China north of 30°N rapidly increases and decreases. The 500 hPa height field presents positive and negative anomaly centers in North China, and the Northwest Pacific subtropical high begins to significantly lift northward or retreat eastward along the coast of East Asia. The upper westerly jet axis at 200 hPa moves north from 37.5°N to 41.5°N or south from 44.5°N to 40.5°N.