ObjectiveTo investigate the inhibitory effect of cryptotanshinone on different maturation stages of Staphylococcus epidermidis (S. epidermidis) biofilm. MethodsThe biofilm model of S. epidermidis was constructed in vitro, the timing of adhesion, accumulating, and maturation was determined; matrix quantity, bacterial metabolism, microstructure of biofilm were detected with semiquantitative adhesion test, XTT assay, and scanning electron microscope(SEM) respectively. ResultsThe timing of adhesion, accumulating, and maturation of S. epidermidis biofilm were 6h, 24h,and 48h respectively; in adhesion period, cryptotanshinone at the concentration of 128μg/mL and 32μg/mL could both obviously reduce the matrix and kill bacteria inside biofilm, difference was statistically significant(P＜0.05)，inhibitory effect of 128μg/mL cryptotanshinone was better than 32μg/mL (P＜0.05), the microstructure was destroyed by both concentrations. During accumulating and mature period, only cryptotanshinone at 128μg/mL could reduce the matrix of biofilm and kill bacteria inside biofilm (P＜0.05), the microstructure was damaged by cryptotanshinone at concentration of 128μg/mL, while 32g/mL of cryptotanshinone had no obvious inhibitory effect（P＞0.05）.ConclusionCryptotanshinone has a certain inhibitory effect on different stages of S. epidermidis biofilm, and there is a certain dose effect.