In research of the optimal walking path and best travel speed of the tangential-axial combine harvester in the field wheat threshing and separating, three typical walking paths of tangential-axial combine harvester which header width was 4.75m were analyzed. It also derived from the point of the minimum consumption of time when combine harvester turned direction at the end of the field. Experiments of the relationship between grain loss rate and the travel speed were conducted, and the mathematical model was established. So were experiments of the relationship between threshing-separating consumption power and the travel speed, and the mathematical model. Based on these experiments and mathematic model, the best travel speed formula was derived. It turned out that rotary walking path should be used to harvest the wheat by the tangential-axial combine harvester. When the harvesting travel speed was less than 1.0 m/s, the equivalent feed rate was less than 7.79kg/s, the total grain loss rate was less than 19.33g/s (that was 0.609%), and the total power consumption of the threshing-separating equipment was less than 83.94kW.