Terrestrial ecosystem has important ecological function and ecological services value. Soil conservation is one of the important ecological service functions of ecosystem, which is benefit for improve ecological environment and realize economy sustainable development. The soil conservation functions of ecosystem mainly include maintaining soil fertility, reducing waterway silt-up and protecting topsoil. Beijing area was chosen as study area, of which the ecosystem changed rapidly. Time series LandSat images were used to analyze the dynamic change of spatial pattern of ecosystem in Beijing area in recent thirty years. By using the method of opportunity cost, the study evaluated the ecosystem service value of soil conservation and analyzed its dynamic change of spatial pattern. Results showed that the order of ecosystem service value in Beijing area was 1978 > 1992 > 2000 > 2010. Because of the close relation with soil erosion, the ecosystem service value fluctuated with yearly precipitation. The main contributors of ecosystem service value of soil conservation were forest, of which the proportion could reach above 80%. The government was committed to promoting the percentage of forest cover, so the forest was the stable contributor for soil conservation in Beijing area.