The catchment above Longyangxia Gorge in the upper Yellow River basin is situated in the northeast of the Tibetan Plateau. Meltwater from snow is the main water supply to the rivers in this region during spring (late March to early June). In this paper, the study target is the inflow to the Longyangxia Reservoir, the largest reservoir in the upper Yellow River basin, during late March to early June. Then a mid-term operational runoff prediction model based on snow cover data from AVHRR images of NORR meteorological satellite and ground surface hydro-meteorological data, called double sifting and stepwise regression model, is presented to forecast the inflow during this period. Examining at the reservoir shows that the forecast accuracy is satisfying. The catchment above Longyangxia Gorge in the upper Yellow River basin is situated in the northeast of the Tibetan Plateau. Meltwater from snow is the main water supply to the rivers in this region during spring (late March to early June). In this paper, the study target is the inflow to the Longyangxia Reservoir, the largest reservoir in the upper Yellow River basin, during late March to early June. Then a mid-term operational runoff prediction model based on snow cover data from AVHRR images of NORR meteorological satellite and ground surface hydro-meteorological data, called double sifting and stepwise regression model, is presented to forecast the inflow during this period. Examining at the reservoir shows that the forecast accuracy is satisfying.