A laser-induced breakdown spectroscopy (LIBS) experimental device for Xuan paper composition analysis is set up, and LIBS spectral lines of Xuan paper and ordinary calligraphy and painting paper are obtained. Combined with NIST database, the composition of metal elements in the sample is analyzed, and the element calibration of spectrum is completed. According to the spectral characteristics of the sample paper, it is found that all samples contain Ca element. However, the number of characteristic peaks of Ca element in ordinary calligraphy and painting paper is relatively small and the corresponding spectral intensity is generally low, which is easy to distinguish. For Xuan paper samples, the spectralintensity of Ca element in different bands is significantly different. According to the distribution law for Ca element in five sample papers, the spectrum is divided into three sections for analysis, and a three- dimensional differentiation map method based on the relative intensity of the three bands of the Ca element is proposed. Based on the comparison of the drop point of the spectral intensity between the tested samples and the established three-dimensional map, the identification and classification of Xuan paper can be realized quickly and accurately.