Based on the sporo-pollen analysis of the surface samples from northern Xinjiang

the Grey Sys- tem

a new mathematical theory

was applied to the research on the sporo-pollen assemblages in the surface samples.The relationship between the sporo-pollen assemblages and the surrounding vegetation was approached by the method of weight index analysis from correlation degree.The corresponding relationship between the sum of ecotope grades index and vegetation zones was induced and rested. This method would henefit the research on the paleo-ecological environment and its evoiution with the aid of sporo-pollen analysis more promptly and precisely.