The invention discloses a turbot pathogenic strain which is Acinetobacter lwoffii, wherein the collection number of the strain is CCTCC (China center for type culture collection) M2010372. The screened Acinetobacter lwoffii is used for preparing an inactivated vaccine. In addition, the Acinetobacter lwoffii, tetraodotoxin pseudoalteromonas and pseudomonas are used for preparing a bigeminy or trigeminy inactivated vaccine which is used for immunizing the turbot ascites disease. The preparation process of the inactivated vaccine for the ascites disease is simple, the yield is stable, the cost is low, and a large amount of inactivated vaccines with high immune effect can be obtained. The immune protective rate of the inactivated vaccine prepared by the method can reach 70%. The vaccine is a pure biological agent, has the characteristics of safety and environment friendliness, and dose not causes medicament residues and environment pollution; and by using the method, the generation and popularization of the turbot ascites disease are fundamentally suppressed, and a technical support is provided for preparing the novel inactivated vaccine for the turbot ascites disease.