Crosstalk is not only one of the main error sources in the polarimetric SAR system, but is also an indicator for evaluating calibration performance. In this paper, to determine the impact of crosstalk on land cover classification, we first retrieve the mathematical relation expressions between crosstalk and the Cloudedecomposition-based scattering characteristic. Then, we verify our theoretical conclusions in a semi-physical simulation based on Radarsat-2 polarimetric data for different land covers. Finally, we perform H/a/Wishart classification on the experimental data. From the ratio curve of pixels labeled differently under changing crosstalk, we can determine the crosstalk requirement that will meet the needs of specific applications.