The complexity and the extension of tasks in enterprise resources planning (ERP) demands an extensive seamless integrations. ERP integration concerns in modeling methodology has been a long-standing problem that has become a burning issue with the advent of e-Commerce, which need to work in collaboration, aiming at a common goal. From this motivation, this paper proposes a unified modeling language (UML) notation driven modeling methodology for developing ERP systems. The methodology consists of two main phases with seven steps：1. project/quality control phase with scheduling, education/change management, and project control steps. 2. development activity phase with requirement definition, requirement specification, analysis, design, implementation, and test steps.