To elucidate the impact of successive subsoiling measures on structural characteristics of black soil and soil carbonpools，seven treatments were set up from 2016 tO₂017:rotarytillage(CK)，1 year of surfacetillage(QS1)，2 yearsof surface tillage(QS2)，1 year of deep subsoiling(SS1)，2 years of deep subsoiling(SS2)，1 year of extra -deepsubsoiling(CS1)and 2 years of extra -deepsubsoiling(CS2).The changes of soilcompaction，bulkdensity，porosity，total organiccarbon，active organic carbon content and carbon pool index in black soil were studied.The results showedthat subsoiling significantly reduced the soil compaction at the bottom of theplow.Under the same depth ofsubsoiling，thecompactness of the subsoiling treatment for 2 years was lower than that of the subsoiling for 1year.Subsoiling treatmentsignificantly reduced soil bulk density and increased soil porosity in 0～ 40 cm soillayer.Compared with the treatment ofsubsoiling for 1 year，the treatment of subsoiling for 2 years increased the soil bulk density and reduced the soil porosity of20～ 40 cm soillayer.In the 0～ 20 cm soillayer，the difference of soil organic carbon content in each subsoil treatmentwith CK was notsignificant，but in the 20～ 40 cm soil layer it increasedsignificantly.Under the same depth ofsubsoiling，the treatment of subsoiling for 2 years increased the soil organic carbon content of 0～ 10 cm soillayer.Compared with rotarytillage，subsoiling increased the soil carbon pool management index.Under the same deep depth，increasing subsoilingyears can reduce the soil carbon pool management index in 0～ 10 cm but increase that of 10～ 40 cm soillayer.Comparedwith rotarytillage，subsoiling can effectively reduce soil bulk density andcompactness，increase soilporosity，improve soilstructure，and improve soil organic carbon conversion efficiency in 0～ 10 cm and soil organic carbon content in deeper soillayer.In all thetreatments，CS2 performedoptimally.