Alpine tree line is the key area to study the relationship between vegetation and climate change. Used the tree ring width data of Picea likiangensis var. balfouriana and Abies squamata at tree line in Dafu, Sichuan, China, based on the method of dendrochronology, the residual chronologies was devoloped. Through the correlation analysis between tree ring index and climatic factors before and after abrupt warming (1995), we anaylazed the changes in the tree ring response of the main coniferous tree species at tree line. The results show that:(1) on the annual scale, the temporal trend of tree ring index and tree resilience of P. likiangensis var. balfouriana and A. squamata before and after abrupt warming was not significant, and there was no obvious divergence phenomenon. (2) On the monthly scale, tree ring index of P. likiangensis var. balfouriana before abrupt warming was significantly positively correlated with the average maximum temperature in December of the previous year, the monthly average temperature from May to July, the average maximum temperature in June, and the average minimum temperature in July; tree ring index of A. squamata was significantly positively correlated with the average temperature in November, the maximum temperature in November, and the average temperature in December of the previous year. Both indicated that tree growth at tree line before abrupt warming was controlled by summer and winter temperature. After abrupt warming, tree ring index of P. likiangensis var. balfouriana was significantly negatively correlated with the average tempreture in November of the previous year, and was significantly positively correlated with the precipitation in February and the average minimum temperature in July; while the A. squamata was significantly negatively correlated with the average temperature in May and the average minimum temperature in May. The correlation coefficient between fir growth and the precipitation in May reached the maximum. All indicated that the growth of P. likiangensis var. balfouriana was still controlled by summer temperature, while the growth of A. squamata was affected by spring drought stress after abrupt warming. If it becomes dry with continuous warming in the future, divergence phenomena of A. squamata maybe appear.