Abstract: The response of annual ring width of Pinus sylvestris var. mongolica plantation grown in the northeast China to the climate change including temperature, precipitation and sunshine duration was studied by response function analysis. The results showed that the change of climate factors from April of the former year to September of the current year might account for about 441% of the variation in the annual ring width. The most important climate factor to influence upon the annual ring width was temperature of the current year. Especially, the response of annual ring width to the temperature in June of the current year was the most significant, whose coefficient was -0350.