Agricultural organic materials are important resources.In order to study the effects of different organic materials on distribution and stability of soil waterstable aggregates,a sevenyears field experiment was conducted in North China Plain.The experiment included six treatments:no organic materials(CK)，crop straw(Str)，compost(C)，manure(PM)，biogas residue(BgR)，biochar(BC).All soil samples were separated into four aggregatesize classes(>2 mm，2~0.25 mm，0.25~0.053 mm，<0.053 mm)by wet sieving,meanwhile the mean weight diameter(MWD)，geometric mean diameter(GMD)，fractal dimension(D)and unstable aggregate index(ELT)of watertable aggregates were calculated.Compared with the control,the application of organic materials in 0~15 cm soil layer not only significantly promoted the formation of>0.25 mm soil waterstable macroaggregates(P<0.05),but also increased MWD,GMD of watertable aggregates.Also,the value of(D)and(ELT)were lower than the control,therefore,the stability of soil structure was significantly enhanced.The macroaggregates(>0.25 mm)and soil organic carbon in bulk soil showed a significant positive correlation (P<0.001).The improvement effects of aggregate stability index and soil structure of BC and Str treatments were the best,while BC and BgR treatments were better to increase soil organic carbon content in bulk soil.The content of soil aggregates and organic carbon was not significant among different organic material treatments in 15~30 cm soil layer(P>0.05).The addition of organic materials could increase the content of macroaggregates(>0.25 mm)and soil organic carbon,enhance the aggregate stabilization of fluvoaquic soil,while improve soil structure and fertility status.