The pathogenic mechanism of white spot syndrome (WSSV) in crayfish, Procambarus clarkii by the investigating activities of immune cells related to innate immune function during infection, which caused by white spot syndrome virus (WSSV) leads to devastating losses in crayfish farming. The WSSV protein VP28, can be used as subunit vaccines that can efficiently protect crayfish from WSSV disease. To detect the functions of VP28 and find a method to prevent this disease in red swamp crayfish P. clarkii, we constructed the plasmid vector of pleVP28. WSSV infection caused parts of the gill epithelium and microvilli to be reduced in number and size or damaged. Meanwhile, the mitochondria, morphology changed, with parts of the cristae diminished leaving large vacuoles. Moreover, electron dense deposits appeared and hetero-chromatinized nuclei could be seen in blood cells with ruptured nuclear membranes and outflow of nucleoplasm. The lymphoid organs of crayfish showed extensive abnormalities. These included obviously necrotic cells and vacuolated cells with hypertrophied nuclei.