Abstract: Gansu Province is a major oat production area in northwestern China. Both oat hay and grain are very good feeds for livestock animals. Due to high variations in topography and physiognomy from east to west of Gansu Province, oat production in the province varies significantly. In order to determine the productivity and adaptability of different oat varieties in different eco-regions of Gansu Province, a 3-year experiment consisting 7 oat varieties (‘Longyan No.1’, ‘Longyan No. 2’, ‘Longyan No. 3’, ‘Qingyin No. 1’, ‘Qingyin No. 2’, ‘Denmark 444’ and ‘Baiyan No. 7’) was conducted in 7 different eco-regions (Tianzhu County, Tongwei County, Xiahe County, Minxian County, Anding District, Hezuo City and Yuzhong County) of the province. The variations in hay and grain yields, growth period, plant height, effective tiller number, panicle length, grain number and grain weight per panicle were recorded and the recorded data was analyzed using GGE-Biplot analysis. GGE-Biplot analysis is a simple and intuitive method for analyzing productivity and adaptability of crop varieties under different utilization purposes in different ecological regions. It can also be used to test the representativeness of trail sites, to enhance the efficiency of experiment studies and to increase the accuracy of experimental results. The results suggested that eco-environment played a vital role in oat productivity. Among the 7 experimental sites in the seven regions, the highest average grain yield (5 671.3 kg·hm^-2) was in Tongwei County while both the lowest grain (1 709.7 kg·hm^-2) and hay (3 301.2 kg·hm^-2) yields were in Anding District. Significant varietal differences were observed in terms of adaptability, productivity and stability in different eco-regions. Different varieties had different performances in different eco-regions under different utilization purposes. ‘Longyan No. 2’ and ‘Longyan No. 3’ performed best in Tianzhu County, Minxian County, Tongwei County and Yuzhong County in terms of hay yield. Then ‘Longyan No. 1’, ‘Longyan No. 3’ and ‘Qingyin No. 2’ performed best in Hezuo City, Minxian County and Tongwei County in terms of grain production. ‘Baiyan No. 7’ was most suitable for Tongwei County in terms of grain production. Among the 7 regions, Tongwei County was most representative of the counties in terms of hay production. Minxian County was the most suitable county in terms of grain production.