With the increasing probability of sports injury in sports training or competition, trunk support strength training has been given more significance, including functional training and rehabilitation training. There are more and more researches on trunk support strength training, but the results are not satisfactory. To make the athletes maintain a high level of sports for a long time and reduce the occurrence of injuries, the biological analysis of trunk support strength training is studied in this paper. In this study, 12 male athletes of a track and field team were divided into experimental group (n= 6) and control group (n = 6). The experimental group received trunk support strength training, while the control group received conventional strength training. Before the experiment, the basic qualities of the two groups of athletes were counted, and the related indexes of functional movements and dynamic balance ability of the two groups of athletes were tested. After 8 weeks, the relevant indexes were tested again to compare the data. The experimental data show that there is no significant difference between the two groups in all aspects of basic quality. Before and after the experiment, the total score of functional movement screening test of the two groups of athletes were improved, the experimental group increased by 21.09%, the control group only increased by 11.03%. In the medium difficulty dynamic balance ability test, the green goal score (A) of the experimental group was the largest, which was 17.4% and 22.26%, respectively; the balance distribution (E) of the control group was the smallest, which was - 0.66% and - 0.72%, respectively. In the dynamic balance ability test of extreme difficulty, the green goal score (A) of the experimental group was the largest, which was 17.95% and 23.75%, respectively; the stability (D) of the control group was the smallest, which was 0.72% and 1.24%, respectively. This shows that the functional movement and dynamic balance ability of the experimental group based on the trunk support strength training is better than that of the control group based on the conventional strength training.