For the problem of the high lose rate of rapeseed with different mature degree by the combine harvester and its short period of harvest, 4SY-1.8 rape windrower was designed ,and a new kind of combined stem conveyer, which integrates the stem convey both in longitudinal and transversal directions, was presented.The overall structure and the working principle of the main parts of a rape windrower were analyzed and the parameters of key components were confirmed such as the reel, the cutting device, the conveyer and vertical roller etc. The field test indicated that rape windrower could harvest mechanical direct-seeding rape and manual direct-seeding rape. When the windrower harvests mechanical direct-seeding rape, the upper windrowing angle and the lower angle of rape stalks are 23.6° and 17.1° respectively, and the difference between both angles is less than 10°, at the same time, the root difference is less than 0.12m. When the windrower harvests manual direct-seeding rape, the upper windrowing angle of rape stalk was is less than 5°while the lower was is less than 2°, and the difference between both angles is less than 5°, furthermore, difference between the rape root is less than 0.1m. This study indicates that swath quality could meet the requirements of the harvesting quality standards and the agronomic requirement.