Forest fires have been increasingly frequent in the 21st century and have been shown to be closely related to tree growth. Therefore, studying the impact of forest fires on tree growth and the effects of different fire intensities on tree response is essential for forest protection. In this study, tree-ring analysis was used to investigate the effects of two forest fires in Nyingchi, Xizang, on the radial growth of Pinus densata and the relationship between its growth and temperature and precipitation before and after the fires. Sample plots of Pinus densata were established in areas affected by mild and moderate fires in Biri and 956, respectively. Using tree-ring analysis and statistical methods, the tree-ring width index was correlated with temperature and precipitation data from 1961 to 2020, and the time series were divided into the pre-fire period (1961-2006) and post-fire period (2007-2021).The results showed that the radial growth of Pinus densata affected by mild fires was sensitive to temperature and precipitation, especially the maximum temperature from March to August, which significantly increased. The radial growth of Pinus densata affected by moderate fires was significantly reduced. Forest fires clearly inhibited the radial growth of Pinus densata, particularly with an inhibitory effect on average and maximum temperatures. The radial growth of Pinus densata affected by mild fires showed a short-term increase but a long-term reduction, while that of trees affected by moderate fires showed a short-term decrease but a long-term increase. In Pinus densata affected by mild fires, there was a significant negative correlation between radial growth and the minimum temperature. Pinus densata affected by mild fires were more sensitive to changes in external environmental factors, while those affected by moderate fires gradually weakened their response. In summary, forest fires had a significant impact on the radial growth of Pinus densata, while also increasing its response to external environmental factors. These findings are crucial for forest protection in high altitude areas.