Effect of applied straw on soil total organic C, extractable organic C and structural stability were examined in an incubation experiment.The results showed that with increase in straw application rate, total organic carbon (TOC), sodium pyrophosphate extractable carbon (SPPC), hydrolyzable carbohydrates (HDC) and hot water extractable carbohydrates (HWC) in soils were significantly increased after 6 month's incubation.Water stable aggregates were significantly increased with increase in straw application rate for all 4 soils studied; clay dispersion rates were significantly decreased in 3 soils except 1 saline soil.Though there were not marked differences between the effects of corn stalk and wheat straw on TOC, SPPC, water stable aggregates and clay dispersion, it seemed that HDC and HWC in soils in wheat straw treatment were higher than those in corn stalk treatment.TOC, SPPC, HDC and HWC were all significantly positively correlated with water stable aggregate and negatively with clay dispersion rates, respectively.In all, however, HWC was more correlated to water stable aggregates and HDC was more correlated to clay dispersion rates than others.