Customer relationship management (CRM) is one of the biggest concerns in a telecom company. Application of data mining can support telecom CRM effectively, and a systematical architecture of data mining has been needed to support every aspects of telecom CRM roundly. To solve this problem, the systematical application architecture of data mining in telecom CRM is established and components of five modules in the architecture are specified in this paper. Data mining algorithms based-on swarm intelligence improved by our own have been adopted in these modules. SIMiner, a self-development data mining software system based on swarm intelligence, is applied in this architecture. Finally, an application example is given to illuminate that telecom companies can make marketing strategies roundly and effectively with the support of the application architecture.