The area of heavy rainfall in the Yangtze River basin during the Meiyu period in 2020 was larger than that in 1998, and the rainfall center was to the north, which was closely related to the two-year abnormal atmospheric circulation and the forcing difference of Sea Surface Temperature(SST). Compared with 1998, the Northwest Pacific Anomaly Anticyclone(WNPAC) at low latitudes in 2020 was stronger and northward with the center eastward, and East Asia's dual resistance was relatively weak, which strengthened the northward uplift of the subtropical high and the southwest airflow on the north side. The existence of the East Asian anticyclone and cyclone pair in high latitude made the north of 30°N controlled by the abnormal northeast wind, and the cold air in the south was also stronger. The water vapor content over the Yangtze River basin was also higher. These circulation differences directly led to more precipitation in 2020 than in 1998 and a northerly center. The Atlantic-West Pacific wave train existed in the middle troposphere for two years, but the wave train was southerly in 2020, which was beneficial to the maintenance of the East Asian anticyclone and cyclone pair and the strengthening of WNPAC and the subtropical high. In 1998, the wave train was northerly and stronger, which was conducive to the stability of the dual blocking pattern. 2019/2020(1997/1998) experienced the central type(eastern type) El Niño event. The former was beneficial to norther WNPAC from June to July than the latter. At the same time, there was a consistent warming between the Indian Ocean and the central Pacific Ocean in 2019/2020, which strengthened WNPAC, and the center shift to the east. In the same period of 2020/1998, there were strong(weak) negative tripole SST over the North Atlantic, which might be one of the main reasons for the difference of the atmospheric circulation anomalies at mid-high latitudes. In 2020(1998), the warm sea surface temperature anomaly(cold anomaly) in the central South Pacific can strengthen(weaken) the cross equatorial flow, which is conducive to WNPAC east and north(west and south)and strengthened(weakened) water vapor transport. In summary, the difference in precipitation during the Meiyu period between 2020 and 1998 might be caused by the synergistic effect of multi-oceanic sea temperature forcing.