The ecological environment of Loess Plateau gully area is fragile,and the water resources are very scarce. In this study, the typical small watershed gully area of the Loess Plateau-Nanxiaohegou basin was selected as the study area. The variation of green water in Nanxiaohegou was revealed based on land use and meteorological data,furthermore,response of green water to climate and land use change was analyzed. Besides,this paper made some researches quantifying the respective contribution of land use and climate changes to green water from 1954 to 2012. The results show that:(1) The mean annual green water of Nanxiaohegou basin is 443.2mm. According to the K-M statistical test, green water of Nanxiaohegou basin shows a decreasing trend, but the trend is not obvious. At the same time, according to the UF and UB curves of the position of the intersection, annual green water mutated around 1978. (2) Interannual variation of green water in different land use types is uneven, among which the green water in forest is the largest, grassland comes second and construction land is the least; the precipitation is a major limiting factor affecting green water in climate variation. (3) According to the results of scenario analysis, the contribution rate of climate and land use change to the annual green water reduction are 123.6% and -23.6%, while the results calculated by the separation of evaluation method are 137.7% and -37.7%. It indicates that the contribution of climate factors for green water change is more than that of the land use factors, while the increase of forest area is the reason for green water increase because of the land use change. The research provides a reasonable and effective theoretical basis for the restoration of regional ecological environment,regional water resources planning and management of the Loess Plateau.