Abstract: In northeast China, the yield of corn straw is large, the working time of returning corn to the field after harvesting in autumn is short, and the straw rot is slow. In order to meet the requirements of rapid returning and rotting for corn straw in northeast China, a straw-fertilizer-mixing and returning machine was developed, which can chop and collect the crushed straw or standing straw, and then mix the chopped straw with N fertilizer. The mixture of straw and N fertilizer is transferred to one side of the returning machine, or stacked in strips, or fed into the furrow by the furrow plough.The parameter design and solid modeling of the straw compressing and collecting and conveying device were carried out by using the 3 d software Solidworks.By analyzing the process of straw crushing and the movement trace of the crushing tool, the optimum arrangement of the crushing tool with the minimum stress was determined.The test results show that when the rotation speed of the straw commination device is 2250 r/min and the forward speed of the field returning machine is 1.27 m/s, the straw returning rate is 95%, the qualified rate of the straw shear length is 95.5% and the non-uniformity of the straw mixed fertilizer is 20.5%. The experimental results verified that the performance of the returning machine meets the design requirements and provide theoretical and practical reference for the improved design of the straw-fertilizer-mixing and returning machine.