The capillary electrophoresis fingerprint (CEFP) of Xiaoyao Pills (XYP) was established by capillary zone electrophoresis (CZE). The quadrilateral method was developed for the optimization of the background electrolyte (BGE), and the running voltage, the compositions and pH of BGE, and so on, were evaluated by the chromatographic fingerprint resolution index (RF). An uncoated fused silica capillary column (70 cm x 75 microm, the effective length of 57 cm) was employed; 50 mmol/L sodium borate-50 mmol/L Na2HPO4-150 mmol/L NaH,PO,-50 mmol/L NaHCO3 (1: 1:1:5, v/v/v/v, adjusted to pH 7.40) was used as the ideal BGE. The detection wavelength was set at 228 nm, and a voltage of 12 kV and hydrodynamic pressure injection in 25 s at the height of 14 cm were applied. The CEFPs from 13 batches of XYPs containing 21 common peaks were obtained with good precision and reproducibility, in which caffeic acid was selected as the reference peak. Cluster analysis indicated that 10 out of 13 batches of XYP samples can be deemed as the reference CEFP (RCEFP). The whole 13 batches of XYP were evaluated by the systematic quantified fingerprint method (SQFM) with the RCEEP as the qualified model. The results indicated that the contents of S10 and S12 were obviously higher, the chemical constituents quantity and distributed proportion of S3 were not qualified, while the others were completely qualified. It is concluded that the method can be applied to the optimization of BGE in CZE in traditional Chinese medicine separation; and the established CEFPs of XYP can be served as a novel reference to identify and control the quality of XYP.