This paper examines the usage and diffusion of Government Credit Information Systems (GCIS) in district-level governments in shanghai. The diffusion of GCIS was studied from a process-oriented perspective. A System Dynamics (SD) model is developed to simulate the relationships of technological, organizational and environmental, and institutional factors on GCIS diffusion under different management policies. A holistic view on the feedback loops, the consequently nonlinear behavior pattern of GCIS usage, and its diffusion in Shanghai government agencies is examined. Our research model and results suggest that workload faced by GCIS users and the tolerable maximum workload have a high impact on GCIS usage, task volume brought by GCIS, work pressure and the perception of technological factors. Different combination of work intensity and the tolerable maximum work intensity significantly influence the system usage. The contribution of our study lies in revealing that the diffusion of GCIS requires a systematic consideration of the business development plan, the GCIS user's workload and the organization's business environment. Flexible managerial incentive strategy will enhance user's work efficiency, thus lead to effective diffusion of GCIS in organizations. The theoretical and practical implications of this study are discussed.