Based on the sea surface temperature (SST) data of Hadley Center, NCEP/NCAR reanalysis data and the temperature data of 160 stations in China from 1951 to 2016, the association and possible mechanism between the North Atlantic SST anomaly (SSTA) tripole and interannual temperature variation in China in summer are investigated.Results show that there is a significant negative correlation between the North Atlantic SSTA tripole and the interannual temperature variation in Southwest China in summer.The Eurasian teleconnection wave train in the middle and high latitudes of the Northern Hemisphere excited by the North Atlantic SSTA "-+-" tripole in summer causes the geopotential height of Lake Baikal to rise, resulting in an anticyclonic circulation anomaly, and causes the geopotential height of East Asia to decrease, resulting in a cyclonic circulation anomaly.Southwest China is located in the east of the anomalous anticyclonic circulation in Lake Baikal and the west of the anomalous cyclonic circulation in East Asia in the middle and lower troposphere.Under the combined action of the two, affected by the anomalous northerly flow, it is conducive to the southward movement and accumulation of cold air.At the same time, the East Asian subtropical westerly jet in the upper troposphere is located in the south, and Southwest China is located in the anomalous updraft on the south side of the jet stream.This circulation configuration leads to the decrease of temperature in Southwest China, and vice versa.