Based on the neural network algorithm and the principle of water and heat balance, combined with hydrological and meteorological data, the suitable scale model of Manas River Oasis is constructed. The suitable scale and current scale of oasis from 1990 to 2020 are analyzed and calculated, and the surface runoff and the suitable scale of oasis from 2021 to 2030 are predicted. The results show that the suitable scale of oasis is 11 003. 3 km², 9 902. 8 km² and 9 075. 2 km² in 1990-2000, 2001-2010 and 2011-2020, respectively, and the current scale is 13 388 km², 14 095 km² and 14 548 km², and the stability coefficients are 0. 46, 0. 43 and 0. 40, respectively. From 2021 to 2030, the average surface runoff of Manas River Basin is 3. 005 billion m³, and the suitable scale of oasis is 8 555. 6 km². The oasis is in sub stable state, so it should be in the appropriate scale to ensure the stable development of oasis in the future.