Aiming at the problem of soil water storage and moisture conservation capacity decline caused by soil compaction, shallow plough layer and plough bottom thickening in Hexi area of Gansu Province, a 1SZL-1600 subsoiling and rotary tillage combined soil preparation machine was designed, which could complete subsoiling, rotary tillage, soil crushing and other operations at one time. This paper introduced the basic structure of the whole machine, the working principle of the storage tank with a certain width in the bottom of the soil, and the main technical parameters of 7 subsoiling shovels with a depth of 25-45 cm, a depth of 8-16 cm and a “man” font arrangement. The main working parts of the machine, such as scimitar subsoiling shovel, rotary tilling knife and articulated mechanism, were analyzed theoretically and designed structurally. The main technical parameters of the qualified rate of the machine were determined, and the field performance test of the whole machine was carried out. The results of the performance test showed that when the soil firmness of the test site was 974.4 kPa, the soil moisture content was 13.26%, and the vegetation coverage before tillage was 35.9 g/m², the subsoiling depth after the operation of the machine was 33.1 cm, the rotary tillage depth was 11.67 cm, the soil bulking degree was 16.04%, and the soil disturbance coefficient was 57.24%. The indicators meet the design requirements and related standard requirements.