Soil carbon and carbon management indices were studied under three different grazing strengths which were set by different distances between grazing-path and the sample points of four kinds of plantations, including artificial robinia, artificial poplar, grassland and berberis aggregate shrub in mountain forest-the arid valley of ecotone in Li County in the upper Minjiang River. The amount of TOC and LOC reduced with the increase of grazing strength in artificial robinia and poplar, but they reduced first and then increased in grassland and berberis aggregate shrub, which depended on the accessibility of livestock and the availability of vegetation under each plantations. With the grazing strength, CPMI decreased and then increased in surface soil, but decreased in 10–20 cm, which decreased by 6.2%–70.41%.