Enterprise environments are complex and multidisciplinary. As the market competition becomes more and more relentless, many business companies have to keep adapting their current and usual processes to new market needs. Almost everywhere organizations are undergoing rapid and significant changes driven by such pressures as customer expectations, new technologies, and growing global competition. When adaptation is needed, enterprises may or may not have any experience with the new business needs, leading to high level risks associated with the adaptation process. There is a strong demand for a comprehensive framework and methodology which can provide consistent support for practitioners to response the rapidly changing environments for finding and keeping their "best practices".Enterprise models play a critical role in integrating business processes, enabling better designs for enterprises, analysis of their performance, and management of their operations. In this research, we introduce a unique framework for enterprise modeling accompanied by an event driven simulation capability. The overall goal of this research is to provide a comprehensive framework to systematically support modern enterprises in adaption of their business practices according to new market needs as well as new technological changes. To achieve this goal, we firstly identify what kind of problems enterprise managers may face when carrying out their adaption processes. We view this problem in a general term as unfamiliarity of managers with the new enterprise operations, organization design and resource arrangement during and after the adaption process. This unfamiliarity causes high uncertainty and anxiety of the business managers in designing and changing to new processes. We propose a unique enterprise model, called PMT (Process Management Technology), to provide a computational and systematic support for industrial or business managers to reduce their unfamiliarity. Our enterprise model is composed of four sub-models, namely, Client Model, Organization Model, Process Model, and Resource Model. While research exists in each of these four areas, little has been done to synthesize the approaches and apply them in a single enterprise model. In this research, we take an integrative approach to enterprise modeling by introducing novel concepts and methods to synthesize the four sub models. We view enterprise business as client and service interactions, where clients send their requests to an enterprise's services for fulfillment. The Client Model represents who the clients are, what they require, and how they request the services of the enterprise. The Organization Model is built based on well known organizational theories in which an organization is modeled as an information processing and communication system structured to achieve a specific set of tasks with limited capacity and bounded rationality. The Process Model is defined by a set of operations, conditional activities, and their successive relations and interdependencies, and finally the Resource Model is developed to represent enterprise non-human resources needed for performing operations. Three in-depth case studies are carried out to demonstrate the effectiveness and utility of the PMT model.