Existing development of rape windrower, which could cut and windrow the plants, has the challenge to improve the trafficability and windrow quality to overcome the complicated field conditions, highlighting a need for exploration of the windrow equipment with simplified structure and stable trafficability. As a solution, the self-propelled middle-placement rape windrower with a high ground clearance crawler was designed. Except for the crawler, the transverse conveying device, cutting system, and hydraulic drive system were also designed and selected. Combined with the rapeseed cultivation agronomy, the laying process of plants was analyzed. The plant parameters, the technical parameters of the windrower and the cultivation agronomy requirements which directly and indirectly affected the quality of plants placement were determined. In order to verify the performance of the windrower, the trafficability test and field functional experiment were carried out. The trafficability test results showed that the average deviation degree of the windrower on hard road surface and soft soil was 0.73% and 1.28%, respectively, and the average turning radius of the windrower under unilateral braking condition was 1.91m and 2.03m, respectively. The windrower could work stable when driving uphill and downhill or overcoming the field ridge and ditch. To verify the function of the windrower, the field experiment was carried out. Under the condition of the forward speed of the machine was 0.7m/s, the reel rate was 30r/min,transverse conveying device rate was 240r/min, cutter crank rate was 320r/min, the average windrowing width was 968.7mm and the height was 389.4mm when harvesting the plants at the mature green stage. Besides, the average laying angle was 13.3°, and the difference between the upper and lower laying angles was 3.5°. When harvesting the plants at the yellow ripeness stage, the average windrowing width and height were 956.8mm and 468.3mm, respectively, while the average laying angle was 13.6°, and the difference of laying angle between upper and lower layers was 4.4°. The placement quality of harvesting rape plants at different maturity stages could both meet the basic requirement of rapeseed production. Furthermore, the soil compaction of each side of the crawler was almost the same, indicating that the mass distribution of the windrower was relatively reasonable. The research result can provide a reference for the structural design and optimization of rape windrower.