Abstract: In order to adapt to the working environment in the hilly and mountainous areas of South China and solve the problems when the full feeding combine harvesters harvest super hybrid rice, such as the problems of threshing drum block, impurity removal, entrainment loss and grain breakage loss, a 4 LZ-2.1 Z-type double speed ＆ double action rice combine was developed to improve the mechanization of rice harvesting. In this paper, the overall design scheme of the machine is described and then the adjustable retractable harvester header, double speed ＆ double action threshing-separating device and cleaning assembly are designed, and finally the key structural parameters are determined. The equipment adopts high/low speed threshing drum, rotary concave plate screen which is composed of double speed and double action threshing-separating device and full feeding way of harvesting. It is able to achieve the functions of holding, cutting, feeding, threshing and cleaning at the same time and meets the requirement of rice harvest in hilly area. Field tests show that the prototype has stable performance, with the loss rate, impurity rate and breakage rate of 1.34%, 0.40% and 0.20% respectively. Each performance index is better than the test standard.