OBJECTIVE： To study the spectrum-effect relationship of inhibitory effects of the extract of Cercis chinensis leaves on the activity of tyrosinase. METHODS： Totally 16 batches of samples of C. chinensis leaves were collected at different harvesting periods， and were heated and extracted with 70％ ethanol. The extract of C. chinensis leaves was analyzed by HPLC. The determination was performed on InertSustain C18 column with mobile phase consisted of methanol-0.1％ glacial acetic acid （gradient elution） at the flow rate of 0.8 mL/min. The column temperature was 30 ℃， and the detection wavelength was set at 254 nm. The sample size was 10 μL. The chromatograms of 16 batches of extract of C. chinensis leaves were matched with Similarity Evaluation System for Fingerprint Chromatogram of TCM 2004 （A edition） to obtain characteristic chromatogram and define common peak. The inhibitory rate of the extract of C. chinensis leaves on the activity of tyrosinase was detected by in vitro tyrosinase dopamine rate oxidation microassay. Partial least squares regression analysis was used to analyze the spectrum-effect relationship of the extract of C. chinensis leaves using common peak area as independent variable， inhibitory rate to tyrosinase as dependent variable. The chromatographic peaks with significant correlation with tyrosinase inhibition effects were screened out. RESULTS & CONCLUSIONS： Totally 16 characteristic common peaks were obtained for the extract of C. chinensis leaves. Tyrosinase activity test showed that the inhibition effect of the extract of C. chinensis leaves was the strongest to tyrosinase when the concentration of the extract was 100 mg/mL （by crude drug）. The common peaks P5， P8， P10， P12， P15， P16 had positive correlation with tyrosinase inhibition effects （correlation coefficient R＞0.1）， while the common peaks P2 and P4 had negative correlation with tyrosinase inhibition effects （absolute correlation coefficient  │R│＞0.1）， indicating compounds represented by these common peaks may inhibit or activate tyrosinase activity.