Abstract: Establishing the relationship between sporo-pollen assemblages in surface soil and surrounding vegetation is an important work for correctly reconstructing paleo-vegetation, paleo-environment and their history of development and evolution by sporo-pollen analysis. The Grey System, a new mathematical theory, was applied to the research on the sporo-pollen assemblages of surface soil. Based on the sporo-pollen analysis of surface soil samples from the. northern slope of the Tianshan Mountain, the relationship between surface soil and vegetation forms was approached by the method of weight index analysis from correlation degree. A table on corresponding relationship between the sum of ecotope grade index and vegetation zones was induced., which tallies with the reality on the whole through thepreliminary test. This method would benefit the research on paleo-ecoenvironment and its evolution with the aid of sporo-pollen analysis more promptly and precisely.