Periprosthetic joint infection(PJI)is a devastating complication after total joint arthroplasty.Although there are many diagnostic methods for this disease, there is no "golden standard" for the diagnosis of PJI. Because of the low sensitivity and specificity of some diagnostic tools, as a result, the interpretation of the results are obscure. In recent years, a number of new diagnostic techniques, such as leukocyte esterase assays and α-defensins have been identified as representative factors of the joint fluid biomarkers, with high sensitivity and specificity, but it has not been popularized in China yet. With the development of technology, there are many scholars and clinicians studying ultrasound lysis and polymerase chain reaction technology to improve the positive rate of culture. But these methods are complicated and low feasibility, more researches are needed for more simple, accurate, stable and practical methods.