Abstract: Major category enrollment is presently an important form of undergraduate enrollment and cultivation system for many colleges and universities in China. Beihang University has been implemented major category enrollment for arts and social sciences students since 2011. "Introduction to Social Security" is the core course for students major in public administration at Beihang University. The positive influence of major category enrollment on the teaching of "Introduction to Social Security" is that major category enrollment optimized the teaching resources allocation for the general courses before learning this course, and cultivated students' ability to examine the social security problems from multiple perspectives. However, the challenges of professional teaching "Introduction to Social Security" from major category enrollment are that some students lacked the rational ability to choose majors, parts of the students had insufficient knowledge reserves before studying "Introduction to Social Security", and students' professional skills and practical ability in social security was challenged. Therefore, it is necessary to take specific measures to reform the teaching method, teaching content, GPA performance assessment, teaching and learning effect feedback of "Introduction to Social Security" course in Beihang University with its major category enrollment background.