In order to solve the problem of lacking structure flexibility and changing initiative in traditional organizational models, the weaknesses in existing researching works was summarized and an ecological organizational model was put forward. Essential factors of ecological organizational model was introduced and they embodied environmental relevance and entity changing features. A meta-model and formal definitions were described. The research methodology that described and forecasted relevancy level and changing aptitude for the organization entities on workflow system ecological environment was presented. Ordering method was regarded as a mathematical tool for organizational situation analysis, and a series of situation parameters were designed for displaying entity changing aptitude. These concepts, model description and methodologies are implemented and verified in an open workflow system-ABCflow.