Abstract: Abstract: Taking a ten-year naked oats field experiment site in Zhangbei county of Hebei province as the test object, this paper studied the effects of different tillage modes (no tillage, subsoiling tillage, and conventional tillage) on the soil physical characteristics and naked oats growth in chestnut soil. The no tillage treatment soil was undisturbed from last year's harvesting to sowing, with 15-22 cm stubbles; broad-spectrum herbicide was used in soil treatment before planting and sprayed in seedling. The subsoiling tillage treatment plowed the soil after the previous year's harvest, used the self-developed 'Parallel rod without wall subsoiling plow' (Patent No.: 2011202468728) with a plowed depth of 15-22 cm, and was sowed and fertilized in the same manner as the no tillage treatment. The conventional tillage treatment plowed with a conventional spade plow after the previous year's harvest, with a plowed depth of about 18 cm; this treatment was also rotary tilled to a depth of 10 cm before sowing and sowed with ordinary seeder. The sowing rate and fertilization were the same as the no tillage treatment. The results showed that the subsoiling tillage and conventional tillage can significantly reduce the soil bulk density from the sowing to jointing stage; in the sowing stage, no-tillage soil bulk density was 1.49 g/cm3, subsoiling tillage and conventional tillage bulk densities were 1.31 and 1.30 g/cm3, respectively. The impact of tillage methods was similar on soil water content. No tillage significantly increased soil hardness. In the jointing stage, no tillage soil hardness was 58.51 kg/cm2, 1.74 times higher than with subsoiling tillage, and 2.53 times higher than with conventional tillage. The test data were analyzed with SAS software, and a model representing the relationship among soil hardness, soil bulk density, and soil water content was proposed. The model showed that under the condition of high soil bulk density (1.53 g/cm3), soil hardness is more sensitive to soil water content, decreasing with soil water content (3.44%-11.94%) from 79.06 kg/cm2 to 28.06 kg/cm2. Under the condition of low soil water content (3.44%), soil hardness is more sensitive to soil bulk density, rising with soil bulk density (1.23-1.53 g/cm3) from 12.46 kg/cm2 to 79.06 kg/cm2. No tillage decreased naked oats' height and leaf area index, and grain number per ear and ears per hectare were significantly reduced, with 413.79 kg/hm2 economic yield, 62.27% and 51.64% of the economic yields of subsoiling tillage and conventional tillage, respectively. Compared with subsoiling tillage and conventional tillage, no tillage was higher in soil bulk density, higher in soil hardness, and significantly reduced in the yield of naked oats. Among the three kinds of tillage, subsoiling tillage provides both ecological and economic benefits.