The development of oyster mushroom business has not been able to meet the increasing consumer demand both in terms of quality and quantity. This happened because of limited funds and application of technology, limited skilled workers, and institutional optimization. Therefore the study aims to analyze: factors that affect the weak coordination function, and Strategic programs in the development of oyster mushroom business. The study was conducted in Enrekang District, South Sulawesi Province. Data were collected by descriptive research through an expert system approach using survey methods. Interpretative Structural Modeling (ISM) used to analyze a strategic program in the development of the oyster mushroom business. The results showed that, Factors causing the weak coordination function in the planning and development of oyster mushroom businesses are Weak formation/training, Institutional disengagement from the start, and Weak Organizing; More strategic programs in planning and developing the oyster mushroom business are Provision/access to capital resources, Oyster Mushroom Price Guarantee, Increasing farmers’ knowledge and skills, and Effectiveness of counseling in the field.