The studies on application of low-molecular-weight organic substances in agriculture，mainly as foliar sprayfertilizers promoting plant growth are widelyknown，there is little information on concurrent changes in soil microbialfunctional diversity andenzyme.Soil microbial functional diversity and enzyme activities can be impacted by soiladditions，which in turn can alter soil fertility andquality.The objective of this study was to investigate the effects of them on microbialfunctional diversity and enzyme activities.Biolog -Eco plates(at 45 day)and methods in enzymology(sampling every15days)were used to acquire the change of soil microbial functional diversity and enzymes withglucose，glycerol and glycine addition(at 25℃).The results revealed that during the period of 15～75 days，the changes of soil enzymeactivity were basically the same with three kinds of low molecular weight organicsubstances.The catalase activity of glucoseaddition treatment was significantly higher thanCK，glycerol and glycineaddition，while alkaline phosphatase activitywas significantly lower after 45 days.Compared with control，glucose and glycine addition，the AWCD of soil microbialcommunity and the indices of soil microbial functionaldiversity(except indexD)were increased byglycerol，while therewere no significant differences among the with control，glucose and glycine addition.Percentage of utilized substrates of soilmicrobial communities were significantly affected by soil additions，especially，the percentage of utilized amines(shortforAM)were decreased to almost zero by glycine and glucoseaddition.The redundancy analysis showed that the activity of soil alkaline phosphatase(at 45day)was positively correlated with microbial functional diversity indicesS，U，H’，CHand AM with the correlation coefficients of0.588，0.669，0.616，0.687 and 0.603respectively，and negatively correlated with D(-0.737)and the activity of invertase(-0.741).Hence，it revealed that different types of small molecule organicaddition have different effects on soil enzyme activities and microbial functional diversity.In addition，compared withothers，glycerol significantly increased soil microbial metabolic activity and diversity indices of soil microbial functional diversity(except indexD).PCA analysis of soil enzyme activity and microbial functional diversity both showed significantdifferences between glycine and other low molecular weight organicsubstances.