Using Jimai 22 as material,the effects of different super absorbent polymers(SAPs)on soil aggregates,microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN)were studied to provide scientific evaluation of the effects SAPs on the soil improvement and the environmental effect.4 different kinds of SAPs at 2 application levels were set up.Soil samples were collected at two typical stages,iejointingstage and harvest time,for analysis of soil aggregates distribution,waterstable macroaggregates(R0.25),mean weight diameters(MWD),geometric mean diameters(GMD),soil unstable aggregate index(ELT),fractal dimension(D),MBC,MBN,soil microbial biomass C/N and soil microbial quotient.The results showed that the amount of R0.25 at jointingstage and harvest time was notably increased by 46.97%~124.89% and 9.35%~75.20%,respectively,compared with the control(CK).There were significant differences among SAPs treatments of different varieties and application levels.The R0.25 of humic acid and SAP compound(FSC)and acrylamide/potassium acrylate copolymer(AS)was notably increased along with the increasing application rate.The influence of organicinorganic SAP compound(WT2)on R0.25 was no significant,while higher application rate inhibited the growth of crops.At the harvest time with relative stable soil property,the MWD and GMD of AS,OSC and FSC treatments were significantly increased,while ELT and D values were significantly reduced.The three abovementioned SAPs could enhance soil aggregate stability and were helpful for the improvement of soil structure.The MBC of AS,OSC and FSC treatments obviously increased from 34.38% to 189.27%,and MBN obviously increased from 48.84% to 334.89%.Soil microbial biomass C and N of FSC treatment were much higher than that of other treatments.The microbial quotient of different treatments ranged from 0.53% to 1.64%,and the carbontonitrogen ratio ranged from 1.50 to 4.66.In conclusion,the application of FSC could effectively improve the proportion and stability of waterstability aggregate,the soil MBC and MBN.Therefore,FSC is more beneficial to soil improvement.