As a fundamental technology for the design and operation of process plants, simulation has been applied through different simulation tools. To perform complex simulation tasks in a technically and economically justified manner, it is sometimes necessary to integrate some of these tools to exploit their strengths. In this work, a “simulation framework” approach is proposed towards systematic support to tool integration. A number of key issues pertaining to simulation tool integration are identified and analyzed. A prototypical simulation framework - CHEOPS is developed to provide a solution to those issues. An application scenario connecting different dynamic simulation tools has been used to explain the integration issues and to guide the development work in CHEOPS.