Abstract: The evolution of ecological carrying capacity (ECC) of western Jilin Province (1995 ~ 2004) was analyzed via set pair analysis (SPA) and principal component analysis (PCA). From PCA, 3 principal components influencing ECC were identified, which were then used to construct ECC assessment framework. The approach degree of optimal scenario aggregate was determined via SPA, which was then used to evaluate the quality of ECC evolution. The results indicate that ECC of western Jilin Province has an increasing tendency, and the approach degree varies from 0.430 0 to 0.501 2, with obvious fluctuations. Improvements in economic efficiency contribute the most to ECC increase, while water resources constitute the main driving factor of ECC fluctuation, and the main factor limiting ECC of western Jilin Province. Compared to 1995, western Jilin Province supports more people with higher economic and living standards in 2004, though at the cost of high resource utilization and severe ecosystem degradation. Thus the approach degree of resource-environment has steadily declined since 1995. The vulnerability of the resource-environment system would severely limit future ECC of western Jilin Province unless effective countermeasures are adopted.