【Objective】 With the quick development of livestock husbandry，there is a rising need for forage sup- plies to feed domestic animals. New forage crops are required in the arid northwest to provide a new supply of nutri- tion，and quinoa is an emerging crop with enormous potential.【Method】 A study on the quinoa's dry matter accumula- tion and feeding quality was carried out between 2015 and 2016 in Zhangye city. The dynamics of dry matter accumu- lation and distribution，the dynamics of relative water content of shoot，the daily increase in plant height and forage quality at different growth stages of quinoa were measured to analyze the dry matter accumulation of quinoa and to ex- plore the suitable harvesting stage for quinoa.【Result】 The results showed that quinoa entered a rapid growth stage after the bud formation stage with a rapid accumulation of dry matter，and the daily increase of plant height could reach more than 10 cm/d. With the growth，the proportion of stem was always below 50%，and leaves and inflores- cences occupied an important proportion in the aboveground part. A comprehensive analysis of the dry matter accumu- lation and forage quality dynamics for quinoa was carried out with the TOPSIS method，and the analysis showed that the appropriate cutting stage was between flowering and filling. It was also found that the bran had a higher mineral content than seed.【Conclusion】 Therefore，in this region，the suitable above-ground part and processed bran of qui- noa could be a potential feed source.