Outsourcing is becoming one of the key approaches in improving cooperation¡¦s operation efficiency. With the continuous improvement on productivity, competitiveness, innovation and higher quality, information-transparency becomes the focus of operation and so is the process information system. For the case studied in this paper, the demand on the process information system is largely increased due to the pursuit of higher competitiveness by adopting more automated processes and decreasing manpower. Moreover, the downsizing manpower has also made the outsourcing of process information system being gradually increased. In this case study company, there are 109 process information systems have been operated smoothly since the establishment of the company and over 90% of them are outsourced. Although Standish Group investigated the 8000 outsourcing software projects in 1995, the results revealed that only 16% of them were well controlled in budget and schedule. However, the outsourcing task is still regarded as the strategic tactics for technology transfer or sharing work loads in the case study company. With this strategy, most of the operation can be monitored under project management and the schedule, quality , cost and man-power had all met the requirement of process information system, furthermore, the core technology transfer were achieved smoothly and explored it in depth. Therefore more process improvement could be realized based on the process condition by the case studied company, not the outsourcing company. A thorough investigation on the execution and the process of the process information system outsourcing with participation design should give more understanding of the achievement. This study employs the theory of outsourcing with participating development to establish the research model. Then, the research model has been revised according to the result of the long-term successful experiences and several project managers deeply interview. In this paper, three outsourcing strategy of process information systems were studied: 1) The new process information system technology transfer for new process¡F 2) The new process information system technology transfer for existing process¡F 3) Out-souring the process information system is for sharing work loads. The key factors of those successful cases were investigated and six participation factors were categorized as follows¡G1) engineering specification and contract; 2) formation of the project team; 3) design of training courses; 4) system function analysis; 5) system analysis &design and 6) project management and control. The details of this study is well documented in the following contents, it can be referenced by another company to improve in their outsourcing process information system more successful. Keyword: Process Information System, Participating Development, Outsourcing strategy