A crustacean PHB2 gene (Lv PHB2) was identified in Litopenaeus vannamei. Lv PHB2 is distributed in mitochondria. The transcription of Lv PHB2 after V. alginolyticus challenge indicated that it is involved in pathogen infection. LvPHB2 may play an important role in shrimp innate immunity. The over-expression of Lv PHB2 could activate p53 pathway, which revealed it might participate in apoptosis regulation.