Abstract: To seek the optimum seeding depth of mechanical direct seeding rape, five operating depth experimental areas are settled: 0, 30-35, 50-55, 70-75 and 90-95 mm. With the help of DPS v6.5, survival percent, growth characteristics and harvest performance of rape were respectively analyzed in each area. The results showed that the indicators of seedling and harvest were correlated with sowing depth. 72 days after sowing in the depth of 70- 75 mm, 81.5 individual plant survived in per square meter. Through measuring parameters of test areas for many times, the average length of main root was 63.62 mm, dry quality of root was up to 0.0732 g, the horizontal growth length of branch tended to be 21.62 mm, the number of branch was 6.89, lodging corner was 19.33°, and harvest yield was 2524.8 kg/hm², the data of rape under the sowing depth of 70- 75 mm was superior to that of the other sowing depth. So the appropriate sowing depth of machine was 70-75 mm. The research provided basic theories for mechanical structural design and relevant agronomic planting conditions.