Artificial afforestation is considered to be one of the most effective ecological methods to increase carbon sequestration, conserve water and soil, and improve water quality. This study focuses on the main coniferous afforestation tree species (Dahurian larch, Pinus tabulaeformis, Oriental arborvitae and Pinus sylvestris var. mongolical) of Zhangjiakou, based on long-term soil and meteorological data, as well as physiological parameters data of afforestation tree species obtained from literature data with similar conditions, and localized the CENTURY model. The validation data derived from literature investigation is used to evaluate the fitting precision of CENTURY model. The results showed that the CENTURY model had a good simulation on SOC, biomass and soil water content, which could be used for the ecological function assessment of artificial coniferous forest in Zhangjiakou. Compared with young plantation, the results of CENTURY model simulation show that the total reserves of soil C, N and P in half-mature forest of Dahurian larches, Pinus tabulaeformis, Oriental arborvitae and Pinus sylvestris var. mongolical increased by 3.37%, 3.98%, 2.84% and 1.82%, respectively, and the soil water contents increased by 151.25%, 73.62%, 41.83% and 94.98%, respectively. The average evapotranspiration of two ages of Dahurian larches (338.85 mm) < Pinus tabulaeformis (399.86 mm) < Oriental arborvitae (400.52 mm) < Pinus sylvestris var. mongolical (401.82 mm) were compared between different forest species. Dahurian larches can be used as the best afforestation tree species in water conservation area. Pinus sylvestris var. mongolical and Dahurian larches were suggested to be promoted in the downstream areas polluted by agricultural production. This study can provide a reference for ecological engineering construction aimed at different ecological function goals.