Abstract: This paper introduces an interdisciplinary teaching reform of Fluid Mechanics for undergraduates majored in Energy and Power, in order to make students understand the professional direction of the major discipline under the background of the major category enrollment. The new teaching reform helps students to select the professional direction. To achieve this teaching goal, the new teaching materials of Fluid Mechanics for undergraduates are optimized, and the blended learning methods include the mixings of the flipped classroom and the traditional classroom, the online teaching and the offline teaching. The teaching effects are evaluated by an online questionnaire and the statistical analysis of the number of students after the professional distribution. The feedback results of the survey and the statistical analysis further confirm that the teaching practice can help students to understand the various professional directions of Energy and Power Categories, and to improve the learning interest and efficiency.