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In order to quantify the difference in mechanical tillage efficiency of plots with different areas and shapes, and scientifically evaluate the potential of land improvement in mechanical tillage efficiency, a set of standard plots was designed, and a 69.83kW Dongfanghong LX950 tractor supporting rotary tiller was selected for tillage, with a working width of 200cm. The mechanical rotary tillage efficiency of plots with different area gradients and shapes was measured by field experiment. On this basis, the coupling relationship and function model of the plot area, shape and mechanical rotary tillage efficiency were established based on regional scale, and the regional mechanical rotary tillage efficiency was modified. The results showed that the regularity of plot shape affected the mechanical rotary tillage efficiency. The more regular the shape was, the higher the mechanical rotary tillage efficiency was. In the same area gradient, the mechanical rotary tillage efficiency of rectangular plots was the highest, followed by trapezoidal plots, and triangle plots were the lowest. With the increase of the land area, the mechanical rotary tillage efficiency was increased continuously. When the land area reached a certain degree, the mechanical rotary tillage efficiency tended to be stable. When the land area exceeded 7000m2, the mechanical rotary tillage efficiency basically remained unchanged. The mechanical rotary tillage efficiency of rectangular and trapezoidal plots was higher, maintaining at 0.25s/m2;the mechanical rotary tillage efficiency of other shaped plots was lower, maintaining at about 0.30s/m2. The mechanical rotary tillage efficiency at the unit level in the case area was 0.27s/m2. Among them, the number of low-efficiency land units was the least, accounting for 7.10%. The number of efficient land units was the largest, accounting for 58.24%. The mechanical rotary tillage efficiency in the western part of the case area was greater than that in the eastern part of the case area, mainly because the land fragmentation degree in the eastern part was higher than that in the western part, the land unit area was smaller and the shape was not regular, which greatly reduced the regional mechanical rotary tillage efficiency value. The experimental results showed that plots with an area greater than 7000m2 were suitable for large-scale mechanized farming, and both the plot area and the regularity of the shape affected the efficiency of mechanical rotary farming. While expanding the plot area, the land regulation project also needed to ensure the regularity of the plot shape.