Abstract: Abstract: Rice is the most important crop in China, which has the largest planting area, the highest per unit area yield and the most total output. The production scale of rice has important significance to the development of grain production safety. Solid ridge is important guarantee for irrigation and rice growth. It can improve the yield of grain crops and reduce the waste of water resources, which is conducive to the construction of standardized farmland in China. At present, the ridge are built still by manual labor in some regions. The ridge building by manual labor have some problems such as poor quality, long operation period, and repeated labor intensity. Ridging operation belongs to a part of tillage operation in the whole production process. With the development of paddy field mechanization, the paddy field machinery ridging technology has become the bottleneck problem for production. Paddy field mechanization ridging is constructed by agricultural machinery to meet the production requirements of rice irrigation and ridge technology. Some Chinese scientific research institutes and agricultural machinery enterprises have carried out researches and designed paddy field ridge machines. These machines take the soil on both sides through the plow or rotary blade and other parts, and compact soil to build ridge by double disc rolling, but they have shortcomings of heavy body, poor flexibility, high power consumption, and limits to the sampling position, which affect the follow-up planting and soil leveling operations. This kind of machine can not fully meet the actual production demands in China. In order to improve the quality and the efficiency of ridging operation in paddy field, and to reduce the labor intensity, the 1DSZ-350 type hanging unilateral rotary tillage compacting ridger was designed, in view of meeting the agronomic requirements of rice planting in the northeast region of China. The overall structure and working principle of the ridger were illustrated and analyzed. The structural design and the theoretical analysis were conducted for key components, such as partial traction hanging adaptive mechanism, rotary tillage ridging adjustable depth transmission assembly, rotary tillage soil- collecting roller assembly and compacting ridging circular assembly. To improve the working performance of ridger and to obtain the best operation parameters, the quadratic general rotary unitized design experiment was carried out with the forward speed and the rotational speed as the impact factors, and the average value of ridge density and the variation coefficient of ridge height as the response indices. Based on experimental data, a mathematical model was built by using the Design-expert 6.0.10 software, the experimental factors were optimized, and the best combination was achieved. Test results showed that the forward speed of the ridger was 1.33 km/h, the rotational speed was 525 r/min, and the average of ridge density was 2 160 kPa, the variation coefficient of ridge height was 4.01%. On the basis, the field test was carried out, and the test results showed that the ridger was characterized by its compact-sized reasonable structure and simple operation. And its ridge had good quality, which was solid and smooth and could meet the requirement of paddy field production. The research results in this paper can provide the theoretical basis and direction for the research of mechanical ridger and its key parts for paddy field.