Abstract: A new type of subsoiling and rotary tilling set for middle-power tractor was developed. The experiments of subsoiling, rotary tilling and combination work were carried out. The experiments show that the arrangement of subsoiler and rotary blade is reasonable, subsoiling disturbance influence width matches rotary tilling width, fluctuation range is small at work and deviation tractor torque has no influence on tractor driving stability basically. The combined machine is able to till the farmland conservatively. The design and experiment provide references for the research and development of new implement matched with large-power tractors.