Abstract: Abstract: Soil salinization has always been considered as a prominent problem of ecological environment in the arid and semi-arid agricultural region. According to statistics, there have been more than 1.0×109 hm2 areas suffering from soil salinization, which are widely distributed in more than 100 countries around the world. So the reclamation and utilization of saline-alkali soil, the same as prevention of soil salinization, has become an important research hotspot for social economical sustainable development. The purpose of improving saline-alkali soil is to enhance soil physical and chemical properties, make it benefit crop growth, and ultimately realize high efficiency and productivity. Among the agronomic improving measures, land leveling accelerates soil water infiltration uniformly, and decreases salt spots. Moreover, the closed drainage method can heighten the irrigation leaching, and evidently inhibit the accumulation of salt on the soil surface. As a soil preparation measure, plowing is documented to reduce soil moisture evaporation and control salt accumulation effectively by cutting the capillary in soil and then loosing cultivated horizon. However, the above treatments are faced with the challenges of heavy workload, high cost, and so on, which increases the agriculture production cost and limits the promotion and application of saline-alkali soil in a large scale. In order to overcome above shortages of the measures to improve saline-alkali soil, a rear suspended passive aerator was designed. The aerator could be applied to loosen soil, enhance soil permeability and improve soil environment. Based on the establishment of kinematics model of five-bar punching mechanism, the constraint condition for key parts was analyzed. Combined with the analysis of working principles and motion characteristics, the structure parameters of punching parts were determined. The optimum machine speed under different punching depth was also calculated, and specifically, the optimum machine speed was 4.7 km/h when the punching depth was 70 mm, while the punching depth turned to 100 mm, the speed was 3.7 km/h. Meanwhile, a passive device was designed to increase the verticality of holes punched by this aerator. The simulation analysis for the verticality of punching process was carried out with computer simulation, and the result showed that the swing angle of punching needle was ranged from -2.2° to 2.3° during the punching process. The computer simulation demonstrated a well punching result under the optimum machine speed condition. A field experiment of prototype was carried out at the experimental station of Gongli Company in Heze City, Shandong Province from August to October in 2015. The matched power of tractor was 75 kW, and an AIC3 600 type model vibration analyzer made in China was installed to monitor the vibration and machine speed of prototype. Six kinds of machine speeds (3, 3.5, 3.7, 4, 4.7 and 5 km/h) were considered in experimental design (3 repetitions). Each experiment was tested 5 times, and the impacts of machine speed on verticality, vibration and separation distance between holes were analyzed. The result showed that the angle between hole profile and horizontal direction ranged from 86.4° to 88.5° under the machine speed of 3-5 km/h, and the coefficient of variation was less than 1.6%. The result also indicated that the hole number within 1 m2 was 51-128, and the work efficiency was 3 600-6 000 m2/h during the punching process. Furthermore, the vibration analyzer test result indicated that the maximal amplitude value was 85 μm, and the maximal amplitude speed was 2.7 mm/s, which met the design requirement.