A study on how the condition of farmland influences operating efficiency of a tractor came up with the following results in the primary experiment. (1) 10m x30m plot of which length is shortest in this experiment, took a maximum of required time per onea plow, whereas 20m x 120m plot, whose length is longest in the same experiment, took a minimum of required time per one a to plow. It reveals, accordingly, that the proportion between width and length should be 1:6; the most desirable proportion that proves to most profitable in terms of time. (2) All the available efforts were made to diminish some unplowed parts of plot to a minimum. It was revealed, however, in the experiment that the ratio of unplowed plot leads to 7.52% in the plot 6; the highest ratio, and 3.44% in the plot 1;the lowe ratio. That shows us that the ratio of availability of land be higher in a more rectangular plot. (3) But even a rectangular plot allows lower ratio of availability in case that the width is narrow. It is showed that a higher ratio of availability can be obtained in when the width of plot is more than 20 meters at minimum. (4) In the operation of plowing by using a tracter, It was also revealed that we could not but have a quite a considerable loss in terms of both the ratio of availability and the required tine for plowing unless we maks a plan to with the unplowed part of plot.