Under the transmission electron microscope, it can be found that different exercise habits will lead to great differences in the distribution ratio of fat muscles in the human body, and lead to changes in the number and morphology of muscle cells and fat cells. However, it is not clear how these changes will affect the body constitution. The purpose of this article is to study the effect of aerobics exercise on the physique of female college students. Through literature research and investigation, this paper briefly introduces the physical problems of college students, including physical quality and psychological quality. The characteristics and significance of aerobics are analyzed. Aerobics can not only exercise the body, but also improve the aesthetic consciousness and artistic accomplishment, helping to form a strong will. The effects of aerobics exercise on the physical fitness of female college students were compared through comparative experiments. The results show that, after aerobics exercise, female college students have improved their performance in all physical fitness items. Among them, sit-ups showed the greatest improvement, exceeding 10 points. The body has also been improved. The chest circumference has increased by 2.8cm, and the waist circumference, hip circumference and leg circumference have all decreased to varying degrees. Psychologically, calisthenics exercise has the greatest influence on irritability index and depression index, making irritability index drop by 1.4 from 3.2 to 1.8 and depression index drop by 0.9 from 3.4 to 2.5. In this experiment, the living conditions of female college students have not remained completely the same, and the seasons and other factors may also affect them, which needs further improvement.