Organizational changes (OC) in "transitional economies" are often characterized by nonlinear complex interactions. How is an organizational change project managed in a complex environment? Literature lacks a systematic answer to this question. This research gap may be due to considerable difficulties in acquiring explicit data about organizational change projects from organizations embedded in a complex system. It is also due to a dilemma of theory building, whether it is adequate to conceptualize a single causal model to explain a change process embedded in complexity. If not, how to improve the theoretical development to fulfill the research gap. In this study, I used a unique action research setting - Battlefield Park, a state owned company in the theme park industry in China. Action research (AR) is a method for solving organizational problems through intervention while simultaneously contributing knowledge with field insights. In the project at Battlefield Park, I was a consultant for the park and a researcher for academia. A serious problem of Battlefield Park is its underdevelopment of publicity. Thus, the AR project primarily concerned the development of its official web site. Correspondingly, certain organizational changes, such as new service programs, were planned. The project at Battlefield Park lasted from Autumn 2012 to Spring 2013, and partial success was achieved with its official web site (http://www.xmzhandi.com/), which came online on February 8,2013. However, until now, some parts of the original plan failed to be realized. By reflecting from the mixed result, this study extends the change implementation literature on how an organizational change project is initiated, planned, and implemented in a complex system. This focus also resonates with a key finding—radical change can result from continuous changes—by Plowman and his colleagues (2007). Specifically, "the dynamic interaction of amplifying actions, contextual conditions, and small changes led to continuous radical change" (Plowman et al., 2007: 515). Yet whether and howamplifying actions lead to change is unclear. To this question, my finding reveals that planned change initiative in complexity results in a temporary limited outcome, because of multiple factors impacting on the complex system. To extend the existing OC literature, I develop a project-based framework of process, present a project focus implementation theory. This thesis also aims to stimulate debates on a popular assumption - "the relationship-based phase will transition to a rule-based phase" (Peng, 2003: 293). For this assumption, reality displays a hybrid picture. A practical problem is that how to reform the Chinese SOEs. I trace the problem back in the literature review, by comparing modern capitalism and China's market institution and following the logic of path dependence to learn why diversity exists. A key notion implied is that the diversified complexities in different regions are a historical result of adaptation and selection. Accordingly, considering that resource sources exist within a specific system can be remarkably valuable in business. Moreover, I develop seven sets of propositions in terms of implementation change theory based on findings of the AR project at Battlefield Park. The propositions illustrate what factors and how they are influential in which stage. A third feature of this organizational change study relies on an application and extension of complexity theory. Complexity theory fits in the ongoing trend of increasing dynamic and nonlinear interactions between institutions and technologies by offering a theoretical account that the other theories are not able to compete with. Particularly, complexity theory makes it possible to model interactions. Furthermore, it provides a process-based view with four constructs—initiating conditions, the far-from-equilibrium state, deviation amplification, and fractals and scalability. These factors are highly flexible in explaining how a change process is developed based on complexity. This thesis makes three contributions to the literature of OC implementation. Every endeavor is believed to be illuminating for both business players and academic readers in understanding and managing organizational change projects in a complex environment.