At present, the content of the three courses, namely, the Fundamentals of Programming, Data Structure, and Algorithm Analysis and Design, is disconnected, which is not conducive to enhancing students' comprehensive algorithmic ability. To break down the knowledge barriers among the courses and strengthen the achievement of the training objectives, a teaching reform idea of content reconstruction of the course group is proposed. Guided by the OBE concept, an algorithm-based course group is constructed, and the main thread of algorithms is integrated into the knowledge of the course group for reconstruction. The course content is connected through cases, and the knowledge points of competitions are deeply integrated into the course group content. The students' interest and learning effect are enhanced through practice. The teaching reform effect is good, as indicated by the improved pass rate, excellent rate of the courses and the achievements in algorithm competitions. Constructing a course group with algorithms as the main thread not only helps to achieve systematic cultivation of algorithmic ability but also provides a practical path for the optimization of the software engineering curriculum system and the achievement of course objectives.