Mathematical expression was established for evaluating anticancer efficacy of samples of Z. nitidum to human tumor cells based on their infrared fingerprints. Chloroform extracts of the root of Z. nitidum from different habitats in China were used as subject samples to do anticancer experiments on two strains of human tumor cells, 7901 and Hela cells. Meanwhile, their fingerprints of infrared spectra were obtained. Screening arguments of backward elimination method was adopted to establish the spectra-effect correlation between infrared fingerprint and pharmacology data. The results showed that deviations of the predictive values from the true values were within ?10% for the two kinds of tumor cells, suggested that there was close correlation between infrared fingerprint and biological activity of Z. nitidum. The model implied that alkaloids in Z. nitidum have main effect on tumor cells.