Order-preserving submatrix (OPSM) is an important qualitative biclustering method of gene expression data. OPSM first sorts the expression values of gene and replaces them with corresponding column labels, and then mines the local patterns of the column label sequence set, where some rows rise and fall together under some columns. This paper proposes an order-preserving subsequence mining method (Charm_Seq) based on the Charm algorithm, and Charm_Seq makes full use of Charm's efficient Itemset-Tidset prefix search tree to mine frequent closed patterns of column label sequence set. Meanwhile, Charm_Cla can effectively improve classification performance by restoring frequent closed sequences to training samples. Experiments were conducted on actual gene expression datasets, and the experimental results verified the efficiency and effectiveness of this method.