Using association rule mining can find the association from huge amount of data in business or other filed.It provides the important information to decision-making.Applying association rule mining to CRM can deepen the analytic function of CRM.According to the enterprises'needs and the characteristics of cross-selling,a constraint-based FP-growth algorithm is presented after analyzing the constraint-based association rule mining.The application of constraint-based association rule mining in CRM can effectively support enterprises to make merchandise planning.