Abstract: In order to improve soil physical structure and promote agricultural cost saving and efficiency in semiarid area,in this experiment,no subsoiling,spring subsoiling 30 and 40 cm treatments and autumn subsoiling 30 and 40 cm treatments were set to explore the effects of subsoiling on soil bulk density,soil water content,threephase ratio and corn yield.The results showed that:（1）There were significant differences in soil bulk density and soil water content among different treatments.Compared with CK,the average soil bulk density of autumn deep pine 30 and 40 cm,spring deep pine 30 and 40 cm treatments decreased by 10.22%,9.49%,4.38% and 5.11% respectively.The average value of soil water content in each soil layer increased by 16.15%,19.94%,2.49% and 6.75% compared with CK.（2）The difference of solid phase,liquid phase and gas phase values of the same treatment at different soil depths reached a significant level.Compared with CK,the soil solid phase of autumn subsoiling 40 cm increased slightly,while the soil solid phase of autumn subsoiling 30 cm,spring subsoiling 30 and 40 cm decreased by 1.22%,21.14% and 13.84% respectively.Compared with CK,the soil liquid of autumn subsoiling 30 and 40 cm,spring subsoiling 30 and 40 cm increased by 9.76%,4.48%,17.75% and 21.61%.The soil gas phase of autumn subsoiling 30 and 40 cm was slightly lower than CK,and the soil gas phase of spring subsoiling 30 and 40 cm was higher than CK.（3）There was no significant difference in ear length and grain number per row among different treatments,but the difference in ear diameter and row number per ear reached a significant level.The ear diameter of autumn subsoiling 30 and 40 cm increased by 6.45% and the number of rows per ear increased by 5.50% and 4.06% compared with CK.Compared with CK,the ear diameter of spring subsoiling 30 and 40 cm increased by 0.65% and 6.02%.The number of rows per panicle increased by 2.19% and 1.38% compared with CK.Yield sequence showed that:autumn subsoiling 40 cm＞autumn subsoiling 30 cm＞spring subsoiling 40 cm＞spring subsoiling 30 cm＞CK.The yield of autumn subsoiling 40 and 30 cm increased by 14.80%and 11.05%compared with CK.The yield of spring subsoiling 40 and 30 cm increased by 9.38% and 8.90% compared with CK.It can be seen that autumn subsoiling is better than spring subsoiling in reducing bulk density,improving soil moisture and maize yield.Autumn subsoiling is more recommended in maize planting in semi-arid area.