Different analytical methods for the determination of chitosan in water-soluble fertilizers by high performance liquid chromatography and spectrophotometry were established.The hydrolysis conditions of chitosan were systematically investigated，and the test results showed that chitosan could be quantitatively hydrolyzed into glucosamine in 24 h with hydrochloric acid(1+1)at 100℃.The linearity range，limit of detection and recovery rate of high performance liquid chromatograply with 1-phenyl-3-methyl-5-pyrazolone(PMP)as the derivatizing agent were 1～200 mg/L，0.07 mg/L and 95%～101%，respectively.For spectrophotometry，they were 0～100 μg，0.47 μg and 94%，respectively.By comparison，the results of the two methods for the determination of water-soluble fertilizers were consistent，and both methods could meet the requirements for the analysis of the chitosan content in water-soluble fertilizers，and high performance liquid chormatography had less interference factors and higher efficiency.In addition，9-fluorenylmethoxycarbonyl chloride was used as another derivatizing agent，and the results were basically consistent with the two methods mentioned above. However，the methods of high performance liquid chormatography and spectrophotometry established in this study are not suitable for the determination of chitosan in water-soluble fertilizers containing nitrate nitrogen.