Using atmospheric data of NCEP/NCAR re-analysis, NOAA Sea Surface Temperature (SST) data, and monitoring data of the rainy season in North China from 1961-2016, the climatic characteristics of the onset date of rainy season in North China (OSDRS_NC) is analyzed. Through synthetic analysis and regression analysis, the relationship between OSDRS_NC and the atmospheric circulation system as well as SST anomalies (SSTA) is analyzed. The results show that the mean OSDRS_NC was July 18 in the past 56 years. The earliest OSDRS_NC was July 6, and the latest was August 10. The OSDRS_NC shows significant inter-annual variation, and its long-term variation trend is not obvious. The OSDRS_NC is closely linked to the activities of the western Pacific subtropical high (WPSH), the East Asian westerly jet stream (EAWJS) and the East Asian summer monsoon (EASM). When the establishment of the EAWJS, the second northward jump of the WPSH, and the northward movement of the EASM are earlier than normal, the OSDRS_NC is earlier than normal, and vice versa. The relationship between the OSDRS_NC and the SST over the Tropical Indian Ocean and the equatorial central and eastern Pacific is significant and stable in the spring and summer. When the Niño3.4 index and the Indian Ocean Basin-wide Warming (IOBW) display positive (negative) anomalies, the WPSH enhances (weakens) and shifts to the south, the Lake Baikal high enhances (weakens) and the EASM weakens (enhances). These anomalies lead to late (early) onset of the rainy season in North China.