To improve the mechanization harvesting level of quinoa and solve the problems of a significant loss rate， high impurity rate， and poor feeding during harvesting of ordinary rice-wheat combine harvester， according to the characteristics of quinoa plants during the harvesting period， a sizeable self-propelled quinoa combine harvester was designed. The machine used flaring type small row spacing chain teeth feeding into the header， combined longitudinal axial flow threshing cylinder， unique woven screen concave， double reciprocating vibrating screen and other devices， cooperation wide bridge， threshing cylinder CVT regulation， and excellent space design to realize the smooth quinoa feeding and efficient threshing separation. Critical components for the design were analyzed， and a field experiment was carried out. The results of the field experiment showed that when the water content of quinoa grain was 14.42%， the threshing rate was 96.83%， the impurity rate was 4.41%， the damage rate was 0.2%， the header loss rate was 1.14%， the entrainment loss rate was 1.73%， the cleaning loss rate was 1.09%， the splash loss rate was 0.16%， the total loss rate was 4.13%. During the experiment， the machine runs smoothly and meets the mechanical harvesting of quinoa. This paper can provide some reference for the design and test of quinoa combine harvester.