This study applies the theory of strategic group and via investigating questionnaires and collecting secondary data, we obtained the variables which related managerial strategies, internal organization, external environment and operational performance. Through factor analysis, cluster analysis, discriminant analysis, and also analyzed the differences of managerial strategies, organization, environment and operational performance, the analytical results can provide the appropriate advises of managerial strategies and related policies for the Credit Department in Taiwan Farmers' and Fishermen's Associations under the drastic competitive environment. The experimental outcomes of this study have shown some important implications such as (1) the Credit Department in Taiwan Farmers' and Fishermen's Associations could be divided into four strategic groups； (2) the managerial strategies and operational performance are significantly different among the groups of the Credit Department in Taiwan Farmers' and Fishermen's Associations； (3) the above differences occur along with the differences on the cognizantional environment and the structure of organization. Therefore, based on the research findings, we have following policy suggestions : the Credit Department in Taiwan Farmers' and Fishermen's Associations must heighten product breadth and idiosyncrasy , enlarge the scale of operation and broaden the scope of coverage； The related units must adjust relevant statute for besetting the Credit Department, increase business articles and objects, resolve dissidence between policy and related units, and fit right to meet the duty. The way of organization must cause the organizational normalization attuning, complication and centralization of the organization. Those policy suggestions let the Credit Department conjugate both internal conditions and external environment, and adopt suitable managerial strategies to promote the operational performance of the Credit Department in Taiwan Farmers' and Fishermen's Associations.