The paper summarizes different estimating methods of soil organic carbon (SOC) storage including methods of soil taxonomy, vegetation types, Holdridge zones, correlative relationship and modeling. The error analysis of SOC calculation was introduced. Based on second national soil survey 2473 soil profiles, adopting soil taxonomy method and two kinds of SOC density, the terrestrial SOC storage in China was estimated. The range of SOC storage in China is between 615.19 and 1211.37 x 10(14) g and the average SOC density is between 10.49-10.53 kg.m-2(for average soil depth of 100 cm) or 11.52-12.04 kg.m-3(for average soil depth of 88 cm). Through estimation and error analysis, the average SOC storage is about 913.28 +/- 298.09 x 10(14) g and the uncertainty is among 20%-50%. Results showed that the differences of SOC estimation and sampling methods are important factors of SOC estimating uncertainties.