Using long-term observation data about climate and soil moisture, the soil water and the land surface evaporation in the last 20 years on loess plateau in eastern Gansu were estimated and the tendency of their variations and the relationship between their variations and climate were analyzed. The results indicated that the inter-annual variation of both soil water and land surface evaporation mainly showed a diminishing trend and an increasing tendency in the few seasons. The rates of inter-annual variation of soil water and land surface evaporation were varying in different seasons and regions. The soil water and the land surface evaporation decreased with temperature rising and increased with precipitation increasing. Response of inter-annual variation of soil water and evaporation to temperature was not sensitive, and response of them to precipitation was very sensitive. The rates of inter-annual variation of soil water and land surface evaporation were keeping with the rates of inter-annual variation of precipitation in different seasons and regions. The precipitation was the main climate factor affecting inter-annual variation of soil water and land surface evaporation.