Abstract: Infectious spleen and kidney necrosis virus (ISKNV) is the main pathogen of mandarin fish Siniperca chuatsi, which hasresulted in a serious economic loss. It is very important to establish a quick method to detect ISKNV in mandarin fish in order to maintain the development of the mandarin fish culture industry. A specific and quick method was established to detect the ISKNV of mandarin fish using nested PCR. Based upon the sequence of major capsid protein (MCP) gene of ISKNV, two pairs of specific primers for nested PCR were designed. The detection efficiency of the nested PCR for ISKNV was also evaluated by using templates with different dilutions from plasmid containing MCP gene. The sensitivity of the nested PCR was 5 fg, which was about 104 times higher than that of one step PCR. The nested PCR method provides an effective diagnostic tool for the detection of ISKNV.