Abstract: To study the effects of conservation tillage on soil physical properties, a long-term field experiment was conducted on Huanghuaihai Plain in a winter wheat-summer maize rotation system. The soil bulk density, hydraulic conductivity, the degree of soil compactness and soil water content was studied under different tillage and crop retention. The results showed that, in the soil profile (0-20 cm), soil bulk density and the degree of soil compactness increased with the decreasing intensity of tillage, compared with long-term no-tillage the degree of soil compactness under tillage once every 2 years or 4 years (CNTW2T, CNTW4T) decreased 40%, 17% respectively, the degree of soil compactness showed a positive linear relationship with the soil depth; conservation tillage improved soil hydraulic conductivity function, soil hydraulic conductivity decreased significantly over time under no-tillage; soil water content under reduced and no-tillage were 0.77%-3.01% higher than conventional tillage. Covering crop mulch reduced soil compaction markedly, improved the compacted soil structure, increased soil hydraulic conductivity, reduced soil water evaporation, thereby, improved soil water-holding capacity. No-tillage had good effects on soil water retention, however, a long-term no-tillage leaded to soil compaction which had negative effects on crop growth. Reduced tillage (CNTW2T, CNTW4T) not only improved soil water infiltration and retention function, but also reduced soil compaction. Therefore, on Huanghuaihai Plain, the application of conservation tillage which consists of reduced tillage and crop retention can improve soil physical properties and enhance soil water conservation effect.