Abstract: To deal with the problems of handling, comfort, convenience and safety for tractor operators in contemporary Chinese tractor operator workpace design, this paper describes the design principles of tractor operator workpace based on anthropometry. Referring to anthropometric data in "Human dimensions of Chinese adults" (GB/T 10000-1988), the 28 body dimensions of Chinese adult males needed in tractor operator workpace design and the values of the mean and standard deviation, and the 5th and 95th percentile values for each body dimension were presented. The simplied biomechanical model of seated tractor operator was built considering the Chinese operator's driving habits, and the model consisted of the straight links which stood for bones and the joints which stood for major articulations. The numerical relationship between standard anthropometric dimensions and link lengths was established, and the comfortable range of angles and the values used in design were determined. The design and layout scheme of seat and controls in operator workspace was developed with the seating reference point, and therefore the expressions of locating seat and controls were deduced. Then the design theoretical values of components' locations were computed. The location of the instrument panel should have an inclination angle not more than 45° and a distance of less than 700 mm from the ellipse center of operator' eyes considering the 95th percentile value in seated posture of operator. In order to accommodate tractor operator stature from 5th to 95th percentile, the provision of 112 mm horizontal and 78 mm vertical adjustment in seat is desirable. Five Chinese tractors, named T1, T2, T3, T4 and T5, were selected as the models, and T1 was chosen to be compared in respect of existing workpace dimensions on the basis of design theoretical values of components. It was found that for the T1, its backrest width and angle deviate from the theoretical values were 130 mm and 15° respectively; the clutch pedal and brake pedal deviate from the theoretical values were 131 and 145 mm in horizontal direction respectively; the steering wheel deviate from the theoretical values was 114 mm in vertical direction; the instrument panel deviate from the theoretical values was 121 mm, 199 mm and 23.2° in horizontal and vertical directions and angle respectively. These values for the T1 had a big deviation compared with the design theoretical ones, and the design of the T1 could not guarantee the operator's sitting comfort, affecting its manipulation of the steering wheel and pedals and normal reading of the instrument panel information, so the workpace design of T1 is not reasonable. The other models were analyzed with the same theory for T1. The result showed that the parameter values for the same components of the models were clearly different, and they also were widely different from the designed theoretical values calculated through anthropometric data. Meanwhile, steering column angles, hydraulic control lever locations, angle between instrument panel plane and horizontal plane, seat pan inclination and seat back angle parameters were quite different among tractor models. Thus, the design of models is unreasonable and it is necessary to be optimized on the basis of Chinese anthropometric data of the tractor operator's population. The paper provides a frame of reference for evaluating the rationality of the design in tractor operator workpace, and a theoretical basis for the optimization design in tractor operator workpace as well.