Abstract:In order to determine the influence of tension spring of four-bars profiling mechanism to the planting depth stability by a no-till planter, the forces on no-till planter unit were analyzed and the planting depth stability mathematic model was established based on the Lagrange Equation. The virtual prototype of profiling mechanism of a no-till planter was established by using the ADAMS software. The spring stiffness, spring pretension force and planting unit mass were optimized with the 2BG-2 no-till planter as an example. The results showed that:maximal pressure of profiling wheel decreased from 1054 N to 934 N, seeder unit mass declined from 120 kg to 102.6 kg, spring stiffness dropped from 12 N·mm^-1 to 10 N·mm^-1. Spring was advantageous to keep the planting depth stable, the bigger spring stiffness coefficient and the smaller change of the planting depth. Through appropriate selection of the stiffness coefficient and spring pretension force, not only guaranteed stable planting depth but also reduced planting unit mass. It can be provided the references for design and utilization of the no-till planter.