Abstract: A retractable rod tooth threshing device was developed to solve problems of high crushing rate, high impurity content and easy to "wrap around braid" and block threshing drum in mechanized harvesting of buckwheat．Threshing device utilized rubbing and brushing action of grooved rod drum and grid concave plate on crops to realize threshing．The crops were well rolled and pushed backwards, avoiding entanglement of straws and improving threshing effect．Threshing device was installed on buckwheat threshing performance test bench, and rotation speed of drum, threshing gap and feeding amount were selected as test factors to carry out orthogonal test．Under this condition, grain breakage rate was 3.42%, and grain loss rate was 0.14%, which met index of mechanized harvesting of buckwheat and provided a theoretical basis for application of retractable rod tooth threshing device and research and development of buckwheat combine harvester．