Abstract: In order to solve the poor growth and low somatic embryo production in the embryogenic callus proliferation of Pinus koraiensis,P.koraiensis embryogenic callus 1-100 cell line was used as material to explore its effect on the somatic embryogenesis and the changes of physiological and biochemical characteristics by adjusting hormone,carbon source and proliferation culture cycle in proliferation medium.The results were as follows:（1）the optimum proliferation condition was 1 mg·L^-1NAA+0.25 mg·L^-16-BA,the best carbon source was sucrose,and the best culture cycle was 14 days.Under the conditions,the largest number of somatic embryos were obtained(166·g^-1);（2）in the process of optimizing proliferation culture,the stored substances provided energy for somatic embryogenesis;There was no significant difference in soluble protein mass fraction between hormone types and their concentrations,carbon source types and proliferation culture cycles;（3）high CAT activity in callus was harmful to somatic embryogenesis,which might be due to excessive accumulation of toxic metabolites such as H₂O₂.