Introduction: Body weight regulation in sports competitions is an essential factor affecting the physical capacity of athletes. Especially in high-level events, the role of weight loss is significant in improving the competitive status. Weightlifters have high anaerobic capacity, high aerobic capacity, high flexibility, and less body fat. In all regular competitions, weightlifters compete against competitors of the same weight class. Objective: This paper investigates the effect of moderate aerobic exercise on weight loss in athletes and the effects of related biochemical parameters. Methods: Twenty weightlifters were randomly selected to conduct a questionnaire survey. The athletes performed aerobic exercises for eight weeks. The collection method and mathematical statistics were used to study body shape and constitution, blood indices, and other relevant data about weightlifters in China. Results: The effect of aerobic exercise on improving the athletes' physical fitness is discussed. The results showed that body weight, waist circumference, hip circumference, and body mass index decreased the most (P<0.05). Waist-to-hip ratio, waist-to-height ratio, hip-to-height ratio, and BMI significantly decreased (P<0.05). There was no significant change in height and fat index (P>0.05). Conclusion: 8 weeks of aerobic exercise and an appropriate diet can significantly improve the body shape index, physical index, and biochemical index of athletes. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.