Actinobacillus succinogenes A3 was mutagenized by ultra high hydrostatic pressure for improving the production ability of succinic acid. The effects of pressure, rate of pressure changes and growth periods on the lethality rate of the strain were investigated. The strain in stationary phase was mutagenized at 200 MPa with the pressure changes at the rate of 50 MPa/min. As a result, a mutation strain Actinobacillus succinogenes B19 was obtained, and the concentration of succinic acid could reach 32.2 g/L, which was 17.9% higher than that of the original strain, and in the meanwhile the concentration of acetic acid was decreased by 11.5%. After six generation, the mutant also has good stability of descendiblity for succinic acid production.