The Qinghai-Tibetan Plateau, often referred to as "the Third Pole" of the world, plays an important role in the Earth's climate system. Chinese pine (Pinus tabulaeformis) forest is one of the most important vegetation types in the subalpine regions of western Sichuan, China, but our knowledge about the response of soil in this forest ecosystem, especially soil total soluble nitrogen to climate change is limited. The effects of elevated temperate (ET, ambient temperature + (2.5±0.5)℃), CO₂ concentration doubling (EC, ambient CO₂ concentration + 350 μmol/mol) and their interaction (ETC) on soil total soluble nitrogen, including nitrate nitrogen (NO₃^--N), ammonium nitrogen (NH₄⁺-N), free amino acid (FAA), dissolved organic nitrogen (DON) and total soluble nitrogen (TSN) of Chinese pine forest soils were investigated by using an automatic micro-climate controlled system.1) Compared with the control (CKP), ET significantly decreased NO₃^--N concentrations in the seedling treatment, and the concentration of NO₃^--N in the 0-15 cm soil layer was lower than that in the 15-30 cm layer. By contrast, ET markedly increased NO₃^--N concentrations in the plant-free treatment, and the concentration of NO₃^--N in the 0-15 cm soil layer was higher than that in the 15-30 cm layer. These results indicated that the absorption of NO₃^--N by Chinese pine seedlings of was enhanced under ET to meet the demands of growth, especially in the 0-15 cm soil layer. This was likely due to the occurrence of more fine roots in the upper soil layer than the deeper layer. NO₃^--N appears to be one of the most important forms of soil soluble nitrogen utilized by Chinese pine. 2) Furthermore, ET, EC and ETC induced an increase in the concentrations of NH₄⁺-N, DON and TSN in the seedling treatment. However, in the plant-free treatment NH₄⁺-N, FAA, DON and TSN concentrations were significantly enhanced under ET; but EC and ETC had little influence on their concentrations. These results suggest that EC and ETC increased NH₄⁺-N, DON and TSN concentrations mainly through the plant roots, but ET acted by influencing both soil microorganisms and plant root systems. 3) NO₃^--N, NH₄⁺-N, FAA, DON and TSN concentrations in the seedling treatment were significantly lower than those in the plant-free group, which might be attributable to the absorption of soil soluble nitrogen by plants to meet growth demands. Overall, in the plant-free group, the signicant increases in NO₃^--N, NH₄⁺-N, FAA, DON and TSN under ET compared with the control (CKS) indicate that warming contributed to the enhanced efficiency of soil microbes. However, in the seedling treatment, NO₃^--N, NH₄⁺-N, DON and TSN concentrations were influenced by both soil microorganisms and plants. Moreover, the amount of soil soluble nitrogen absorbed by Pinus tabulaeformis mainly varied among the different forms of nitrogen.