Fluorescence spectroscopy has achieved great successes in the study on the interaction of drugs and DNA in both quantitative analysis and qualitative analysis. While the fluorescence probe technique can be used to measure the intensity of drugs-DNA interaction, because the injected drugs can change the fluorescence intensity of the probe. In this paper, the authors use berberine as a probe to measure the interaction intensity between some anticancer drugs and DNA, calculate the constant D and determine the effects of those drugs. In addition, the authors point out that this method can not be efficient for certain drug solution.