Forest is one of the most complicate terrestrial ecosystems in the world and plays an important role in sustaining the global life system. Forest ecosystem services can provide economic benefits both directly and indirectly. The valuation of forest ecosystem services has become a hot topic in ecological economics research. There has been a growing literature on valuation of forest ecosystem services in the past few decades. In each case, the researchers gave important insights into the spatial and temporal changes in forest ecosystem services. A few researches indicated that the ecosystem service function has close relationship with biomass, but previous evaluations of forest ecosystem services did not take this point into account. Shanxi Province was chosen as the study area. The objectives of the study were therefore: (1) to assign specific value coefficients for the forest ecosystem services; (2) to estimate changes in the matter and value quantity of forest ecosystem services in 1995, 2000 and 2005; and (3) to provide information and advices to support forest sustainable development policies in Shanxi Province. The results showed that the total value of forest ecosystem services in Shanxi Province were 377.24×10⁸ yuan in 1995, 428.79×10⁸ yuan in 2000, and 501.12×10⁸ yuan in 2005, representing an increase of 123.88×10⁸ yuan from 1995 to 2005; the value of unit area forest ecosystem services were 2.60×10⁴ yuan in 1995, 2.72×10⁴ yuan in 2000, and 2.93×10⁴ yuan in 2005, representing an increase of 0.33×10⁴ yuan from 1995 to 2005. During the ten years, the increasing value of forest ecosystem service was contributed mainly by Lithocarpus (39%), Chinese pine (17%) and Spruce (14). The areas of forest in Shanxi Province increased 18% form 1995 to 2005, but the matter quantity and value of forest ecosystem service increased 33%, which showed that the forest ecosystem in Shanxi Province has very important service function. During the ten years, the matter and value quantity of unit area forest ecosystem services in Shanxi Province increased about 13%; among contribution of value of all ecosystem services, the order of value is below: water conservation > biodiversity conservation > soil conservation > fixing carbon and releasing oxygen > decontaminating atmospheric environment > accumulation nutrient. If not taking the biomass factor into account, the estimated matter and value quantity of forest ecosystem services in Shanxi Province would be obviously higher than actual quantity, which indicated that the biomass has great influence on the forest ecosystem services.