We propose for the first time that curve-fitting method should be applied to the quantitation of overlapping peaks in chiral separation by high performance liquid chromatography (HPLC). We have examined the separation of eight isomers of cyfluthrin on a chiral stationary phase (CSP), and found that in comparing with the perpendicular-drop method, the accuracy of quantitation of overlapping peaks with curve-fitting was much higher. Generally, errors in peak area measurement using the perpendicular-drop method become larger as the degree of peak overlap increases. Meanwhile, by using curve-fitting method errors have no apparent difference for different degrees of peak overlap. Generally, for the same chiral compounds, although the resolutions are different with different mobile phase strength, the results of peak areas are the same by using curve-fitting method.