Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to detect and identify four fish viruses, fish iridovirus, viral hemorrhagic septicaemia virus (VHSV), viral nervous necrosis virus (VNNV), hirame rhabdovirus (HRV). Four viruses were detected by PCR with each specific primers. Identification of iridovirus was achieved by digesting the PCR amplified fragment with a restriction enzyme ApaⅠ. It was possible to distinguish positive from false positive PCR amplicons of VHSV by RFLP of PstⅠ or HindⅢ restriction enzymes. VNNV was identified using RFLP of BamHⅠrestriction enzyme and HRV was identified by XbaⅠ restriction enzyme. This approach can be used for more rapid, simple and specific diagnosis of fish viral diseases.