As a powerful molecular biological tool,polymerase chain reaction(PCR)can detect pathogens in intraocular fluids at the early stage of infectious uveitis cases. It takes tiny amount of samples, short examination duration with high detective sensitivity and specificity. PCR detection of pathogens is superior to routine diagnostic approaches such as serological antibody detection and pathogen culture. It provides a potential method in early diagnosis of infectious uveitis and evaluation of therapeutic efficacy.