Dingxi City of Gansu Province is a typical ecological fragile area and a famous poverty-stricken city in China. Because of its harsh natural environment and traditional farming ideas, economic development there has been slow. With the implementation of “Agricultural Supply-side Reform” in China, some regions have developed grassland agricultural production mode (GAPM) by introducing grass into fields, but there are still many regions that conform to traditional cultivated land agricultural production mode (CLAPM). In order to find out the suitable agricultural production mode for Dingxi City, two production modes, GAPM and CLAPM there were studied. This study used opportunity cost method and alternative engineering method to compare the ecological benefits of the two production modes. The results showed that the values of GAPM to provide products, conserve soil, regulate climate, sequestrate carbon and product oxygen were 479.31 yuan / mu,483.51 yuan / mu,1.94 yuan / mu,394.6 yuan / mu, and 393 yuan / mu respectively, better than CLAPM. Therefore, GAPM in Dingxi City has been effective, indicating a new suitable industrial mode for Dingxi city and other regions with the same requirement of agricultural industry updating.