In order to reveal the quality of greenhouse soil for vegetable cultivation,the relationships between soil microbial community structure,functional diversity,and soil quality of vegetable greenhouse for different planting years (3,5 and 7 a) and uncovered vegetable field (CK)were investigated byphospholipid fatty acids(PLFAs)analysis and Biolog-Eco micro plate method in Wuling area of Guizhou Province,so as to provide a scientific basis for exploring the microbial mechanisms underlying soil quality degradation.Results showed that as the greenhouse vegetable planting years increased,total nitrogen,ammonium nitrogen and nitrate nitrogen contents gradually accumulated,soil acidification was obvious.The soil microbial biomasss carbon and nitrogen contents were the highest for the planting 3 a treatment,which were 74.51% and 4.17% higher than those of CK;the amount of soil fungi increased,and the bacterial/fungal decreased gradually,which led to the decrease of soil stability.The results of hierarchical clustering and principal components analysis(PCA)showed that the planting years had significant impacts on the soil microbial community structure.The soil microbial community structures of the planting 3 a treatment and the control group showed significant differences from those for the planting 5 a and 7 a treatment.The average soil well color development(AWCD)and the microbial functional diversity index(Shannon index,Simpson index,McIntosh index) of the planting 3 a treatment were higher than those of other planting years treatments. The main carbon sources absorbed by the greenhouse soil were amino acids and carbohydrates,and the planting years of 3 a treatment had the highest capacity to use all carbon sources.pH value,organic carbon content,total nitrogen content,and C/N were the main factors affecting soil microbial community structure and microbial metabolism.According to the comprehensive analysis results,the soil microbial community structure and functional diversity changed significantly,and the soil microecological balance was disturbed,impeding the efficient and sustainable use of greenhouse soil after greenhouse vegetable planting 3 a.