Abstract: Test procedures of the operation quality of tobacco harvesters are technical specifications that form the basis for evaluating their performance and effectiveness, and the length of test area is a key parameter that must be specified. To determine the appropriate length of the test area for tobacco leaf harvester, field experiments were conducted to analyze the differences in average values and trends of coefficients of variations for rates of broken leaves, miss-harvest leaves, fallen leaves, damaged stalks and the value of comprehensive operation quality index across different test area lengths. The results showed that with the increasing length of the test area (20.0-100.0 m), the average rates of broken leaves, miss-harvest leaves, fallen leaves and damaged stalks decreased, while the average value of comprehensive operation quality increased. The coefficients of variations for rates of broken leaves, miss-harvest leaves, fallen leaves, damaged stalks and value of comprehensive operation quality exhibited decreasing trends. Among them, the average rates of broken leaves, miss-harvest leaves, fallen leaves, damaged stalks and the average value of comprehensive operation quality in the test area with a length of 60.0 m showed no significant difference compared to those in the test areas with lengths of 80.0 m and 100.0 m, but exhibited significant differences compared to the test area with a length of 20.0 m. Moreover, the coefficients of variations for all five indicators in the test areas with lengths of 60.0, 80.0 and 100.0 m were lower than those with 20.0 and 40.0 m. Therefore, the appropriate test area length for tobacco harvester should not be less than 60.0 m.