Abstract: 【Objective】 Aiming at the problem of wading water harvesting and low harvesting efficiency of watercress in cold winter,an automatic watercress harvesting machine was designed to realize efficient and orderly harvesting of watercress without wading.【Method】 An automatic watercress harvesting machine with double floating platform,differential drive with double helix pulp and lateral harvesting structure was designed. The maneuverability of the watercress harvesting machine was verified by experiments,and the relationship between the orderly degree of watercress harvesting and cutting width,moving speed and harvesting efficiency was analyzed.【Result】 The order degree of watercress was higher when the cutting width and moving speed were smaller,and the harvesting efficiency was directly proportional to the cutting width and moving speed. Under the condition of orderly harvesting,the maximum harvesting efficiency was about 900 m2/h,which occurred at the cutting width of 0. 25 m and the traveling speed of 1 m/s. The damage rate is independent of the cutting width and speed.【Conclusion】 The designed watercress harvester can realize automatic harvesting of watercress,and its harvesting efficiency is 19 times that of manual harvesting.