Abstract: Three such cover crops，two perennial legumes (white clover and alfalfa) and a perennial gramineous grass（tall fescue）were sown inter-row in Cabernet sauvignon vineyard，with clean tillage as the control. The effects of cover cropping on microbial populations，soil nutrient contents and their relationships were studied. The results showed that soil microbial quantities in cover cropping treatments were increased，among which azotobacter and cellulose-decomposing and bacteria microorganisms increased by 223.4%，83.4% and 68.1%，respectively，but only slightly changing for actinomyces，compared with bare soil（control），the soil from white clover and alfalfa plots showed higher quantities of microbial populations than tall fescue polt，and significant differences were observed between the two cover crop treatments and the control（except actinomyces）. Also，it indicated that cover crop treatments had higher soil organic matter content，but reduced available P and total P. For white clover and alfalfa treatments，the contents of soil hydrolyzable N，total N，available K increased evidently，while decreased for tall fescue treatment. All kinds of soil nutrients showed significant or very significant position correlations with soil microorganism factors，except that soil available P were no significant correlations with fungi and azotobacter. Path analysis indicated that in the vineyard intercropping system，soil cellulose-decomposing microorganisms was the main factor affecting the accumulation of soil organic matter，soil actinomyces was the most important factor affecting soil total N，hydrolyzable N，total P，available P and available K.

Key words: vineyard, inter-row cover crops, soil microbial populations, soil nutrients