Abstract: Abstract: No-tillage seeder mainly uses the 2 ways of cutting and removing the straw to ensure seeding smoothly by now, and thus there are many problems: Higher power, environment pollution, twining and blocking of straw, and so on. To this end, a mechanism based on the special trajectory requirements was developed to enable the soil opener to penetrate into the surface without any treatment of the surface covering, which could lay substantial foundation for the implementation of injection-free no-tillage planting pattern. First of all, the analysis of mechanism aimed at the special trajectory was carried out and the five-bar mechanism was confirmed as the formation mechanism of trajectory. Moreover, the mathematical model of five-bar mechanism was set up, and the basic existence conditions and spatial constraints of double-crank and uniform five-bar mechanism were analyzed on the basis of the model. Given the feasible region of relative trajectory of the cavitation endpoint, and combined with the mechanical design module and knowledge engineering module of CATIA (computer aided three-dimensional interactive application) software, the parametric model was set up, the movement was simulated and the trajectory for five-bar mechanism was drawn. Subsequently, the distribution characteristics of region trajectory of cavitation endpoint were researched by the method of region localization of trajectory; the influence of the parameters on the trajectory was researched by the method of numerical cycle and comparison, and combined with the constrain conditions, the combination of structural parameters and operation parameters was obtained corresponding to different distance; on the above condition, the effective operation trajectory at the vertical direction changed from 251.2 to 344.7 mm. In May, 2016, the experiments were carried out with the prototype in the Soil Laboratory of the College of Engineering, Northeast Agricultural University. The conditions were set as follows: The length of mulching straw was 3 m and the average thickness of straw was 15 cm. In order to simulate the actual working condition in the field, the straw was scattered on the soil surface, and part of straw was stuck in the soil layer. The whole process that the soil opener device perforated through the straw until the straw was removed completely was shot by high-speed camera with the same planting spacing under different setting angle of soil opener of five-bar mechanism; the experiments were also conducted on different plant spacing respectively, and then the experimental images were observed and analyzed. Combined with the motion simulation of CATIA, the soil opener setting angle of five-bar cavitation mechanism was obtained, which could meet the requirement for the best hole-forming points. The angles were 128?, 128?, 134?, 134?, 134?, 128?, 128?, 128?, 128? and 122? respectively corresponding to the spacing of 60, 80, 100, 120, 140, 290, 310, 330, 350, and 370 mm. Research showed that the formation mechanism of trajectory in the process of no-tillage seeding based on the five-bar mechanism could drive cavitation device to complete the operation under the condition of straw returning drastically, and perforate through the straw effectively and form cavitation as required, with fewer scraping phenomena. It is confirmed that the region localization of trajectory can improve the solution efficiency of parameters combination of the five-bar mechanism, and also provide the effective method of solving the parameters of five-bar mechanism according to the ratio of long axis to short axis of similar ellipse trajectory.