Abstract: In order to meet the demand of the market, the deepening type of rotary tiller was researched　and developed by synthetically applying present theory of the terramechnics and design experiences of rotary tiller, including the adoption of suitable bigger diameter and slower running of the rotor, design of unstandard blade, number increase of blades in the circuity of the rotor, reduction of advancing speed of the unit, addition of trailed soil cutting parts, and utilization of fitting state of soil for tillage etc.. Those were special measures. Besides, additional general measures were taken to strengthen transmission system, increase strength and rigidity of the frame. Those measures were taken on links of design and manufacture to achieve good results, such as a complete set to control load and power expense to keep power balance of the unit, to realize predetermined working depth, and to satisfy agronomy requirements.