The diagnosis of the peri-prosthetic joint infection(PJI) has always been very difficult. Quick and accurate microbiological diagnosis is very important for the treatment of PJI. Fluorescence in situ hybridization (FISH) technology has high sensitivity and specificity, which can visualize the morphology of bacteria and its biofilms, can detect multiple infections and drug resistance genes, and has the advantages of short detection time, simple procedures and so on, which provides a new direction for PJI diagnosis. However, FISH technology also has some shortcomings, such as the lack of uniform specimen processing methods, high false positive rate caused by autofluorescence. Whether FISH technology can become routine work for clinical microbiology still needs further study.