Jinsha Site is located at Jinsha Cun in the western part of Chengdu City. This site is considered to be the center of ancient Shu Country during the period from the late period of Shang Dynasty to Xizhou Dynasty (about B.c.1100–770 yrs). Thirty-one palynological samples collected from two profiles (WT7908 & IT8305) in Jinsha Site were analyzed. The results show that samples from profile IT8305 contain abundant pollen and spores. The palynological assemblage shows that pteridophyte spores are abundant with the percentage of 60.3% and dominated by Athyraceae, Polypodiaceae and Pteris. The pollen of herbs is 24.8% in percentage, with the abundant pollen of Melastomataceae. The pollen of trees and shrubs has the percentage of 4.2%, with Pinus and Betula mostly. The pollen of aquatic plants reaches 0.7%, including Zygnemataceae, Commelinaceae and Typha. Based on the palynological data of Jinsha Site, the subtropical climate in Chengdu plain is divided into two stages, with the warm and wet condition in the first stage and more humid and hot in the second one. The climate of Jinsha Site 3000 yrs B.P. ago is also reconstructed by the coexistence approach quantitatively: the mean annual temperature is 17.7–19.8ºC, mean temperature of the warmest month 21.7–28.6ºC, mean temperature of the coldest month 11.5–11.9ºC, difference of temperatures between coldest and warmest months 12.1–14.9ºC, mean annual precipitation 993.3–1113.3mm, mean maximum monthly precipitation 224.6–268.1mm, and mean minimum monthly precipitation 6.9–14.1mm. The mean annual temperature in Chengdu region is suggested to be 1.7–2.8ºC higher than the present value, but the mean annual precipitation is in conformity with recent one.