Abstract: Abstract: Dissolved pulp refers to pulp of high cellulose content which is used to manufacture various cellulose-derived products such as regenerated fibers or films (e.g., Viscose, Lyocell), cellulose esters (acetates, propionates, butyrates, nitrates) and cellulose ethers (carboxymethyl-, ethyl-, methyl-celluloses). With the rapid development of the global economy and a constant increase in population, the overall demand for dissolved pulp is rising. Dissolved pulp is generally made by the prehydrolysis kraft and acid sulfite processes comprising additional purification stages such as hot and cold caustic extraction. Dilute sulfuric acid is the most commonly used solvent for prehydrolysis of biomass to produce the dissolved pulp. However, cellulose is seriously degraded and the equipment is corroded while the prehydrolysis with sulfuric acid is performed. Oxalic acid, as an organic acid, has a better prehydrolysis selectivity than some mineral acids such as sulfuric acid or hydrochloric acid. The purpose of this paper is to clarify bamboo lignin removal during the bamboo prehydrolysis with oxalic acid to improve the prehydrolysis process for dissolved pulp. The acid-insoluble lignin contents were determined with 72% H2SO4 according to the TAPPI standard test method (T 222 om-06) at different prehydrolysis periods. The distribution of pseudo-lignin on the surface of bamboo fibers was observed by FE-SEM. The chemical structural changes of bamboo lignin were studied by means of CP/MAS 13C-NMR. The results show that the yield decreased with the extension of prehydrolysis time as most of the hemicellulose and a little of the lignin and cellulose were degraded under the acid prehydrolysis conditions. As an increased amount of oxalic acid was applied for prehydrolysis, an increased drop of the yield was obtained. The lignin content based on the prehydrolysed bamboo chips increased with the extension of prehydrolysis time due to a predominant degradation of hemicellulose, the increased amount of oxalic acid and the higher lignin content. However, the lignin content based on the bamboo chips increased dramatically after an initial decline with the extension of prehydrolysis time due to the condensation between the lignin degradation products and carbohydrates, and the formation of pseudo-lignin. As an increased amount of oxalic acid was used for prehydrolysis of bamboo, a greater increase in the rate of lignin content was obtained. The bamboo lignin has more phenolic hydroxyls due to the breakdown of aryl-ether bonds (β-O-4) during the oxalic acid prehydrolysis of bamboo. The pseudo-lignin originating from carbohydrates including cellulose and hemicellulose could attach to the surface of bamboo fibers in the form of microspheres.