Abstract: An experiment was conducted to study the effects of plant growth regulators (PGRs) and osmotic adjustment substances on somatic embryogenesis of Fraxinus mandshurica Rupr. by changing the kinds and concentrations of them, which was taken cotyledon of mature zygotic as explants. PGRs were the essential factors for somatic embryogenesis of F.mandshurica on the induction medium. The induction medium higher osmotic stress was beneficial to induce somatic embryos. Under PGRs, the induction medium of highest SSEs induction rate was added with 75 g·L^-1 sucrose. The somatic embryo was induced by the induction medium was added with 100 g·L^-1 sucrose had higher differentiation rate on the differential medium contained BA. This study laid the foundation in increasing SE induction rate and improving the status of somatic embryogenesis and optimizing the somatic embryogenesis system of F.mandshurica.