The distribution laws of soil enzymes of Talimu Desert Highway Shelter-forest and the effects of soil or- ganic matter on them were studied. The results show that the activities of soil enzymes increased sharply, the dis- tribution of soil enzymes had distinct laws with time elapse and variation of space,and soil structure and nutrient status were improved with greenbelt set up under condition of irrigating by saline water. By analysis of path coef- ficient, soil proteinase had the largest direct effect on soil organic matter, neutral phosphatase, uraease, invertase, alkline phosphatase and catalase ranked in order. The interactions between pairs of neutral phosphatase-alkline phosphatase, alkline phosphatase-neutral phosphatase, uraease-neutral phosphatase, proteinase-neutral phos- phatase had larger effects on soil organic matter.