Abstract: The study is to test and analysis the surface electromyography in 24-style of dynamic Swiss ball exercises,for study the stimulation intensity of four major trunk muscle of swimming athlete in Swiss ball practice.The expectation of the study is to provide some valuable reference to swimming athlete's Swiss ball exercises.10 healthy National 1-level swimming athletes volunteered to participate in the study.Use BIOPAC-MP150 physical instrument to test the subjects` abdominal muscle,obliquus externus abdominis muscle,erector spinae muscles and Multifidus muscle in 24-style Swiss ball exercises,calculating the muscle AEMG value of subjects.Through the cluster,24-style Swiss ball exercises are divided into four types,draw on each type of Swiss ball exercises in the graphics in plane right angle coordinate by using the AEMG data,the results is that the first category of exercises is turn to the little more obliquus externus abdominis muscle and erector spinae muscles leading with the power of exercises;The second category of exercises is turn to the little more erector spinae muscles leading with the power of exercises;The third category of exercises is turn to the abdominal muscle and obliquus externus abdominis muscle as the major leading with the power of exercises;The fourth category of exercises is turn to the erector spinae muscles and Multifidus muscle as the major leading with the power of exercises.TheConclusionsis that 24-style Swiss ball exercises to the trunk's core four muscle group of AEMG value are in 10% ~ 50%,all belong to a low load strength of practice;using the method of plane right angle coordinate to figure area computation can calculate the stimulus strength value of trunk muscle group of Swiss ball exercises,can simply and intuitively showing the trunk muscle stimulus values on Swiss ball exercises.The coaches and athletes can accord the graphics area selecting the appropriate value practice used in training;The key characteristic of Swiss ball used in swimming,is that Swiss ball can connect closely with swimming technical and provide no fixed environment similar likes water.Athletes and coaches shall obey the training principle,through diverse of means let Swiss ball exercises become more reasonable to adapt the swimming training.