As part of the study of Islamic law, ushul fiqh demands that one be able to practically handle religious issues by using the ulama's defined principles of Islamic law. Applying Islamic legal theory practically calls for critical thinking abilities. Therefore, this research aims to find a learning formulation in Ushul fiqh that integrates efforts to improve thinking skills. To achieve this goal, action research was chosen as a research design which was carried out in three research stages, namely pre action, implementation action and post action. This design was chosen considering that the context of this research is oriented towards finding solutions to learning problems. This research involved 35 prospective Islamic religious education teachers who took Ushul Fiqh courses from one of the government-owned Islamic universities, which is quite popular in Indonesia. Data was collected through surveys and semi-structured interviews which were analyzed using a descriptive quantitative approach and qualitative with content analysis. This research produced seven stages as learning formulations that need to be implemented in the ushul fiqh learning process. The study concludes that the proposed seven steps effectively elevate students' thinking skills to the Higher Order Thinking Skills (HOTS) level while applying usul al-fiqh principles. The findings suggest a promising pedagogical approach for cultivating advanced thinking skills within the context of Islamic law education. The main contribution of this study is to present a practical methodological guide regarding the steps for teaching usul fiqh, which is oriented toward improving students' thinking skills.