The purpose of this study was to examine the kinematics variations occurring in each segment of the body through three dimensional cinematography of national team level tennis players flat service motion. The object, also, was to provide data for instructing players by identifying the types of service motion. It can be said that important things in a service motion are power and precision, and at the point of impact, the position of the racket face must be congruous with its angle of incidence. In order to do timing and rhythm must form mutual harmony. With these scientific analysis and method, Coach and Instructors must provide profer guidance and teaching for tennis players. Seven tennis players of the Korea Armed Forces Athletic Corps(KAFAC) were the subjects of the study, and film shooting was done by using two high-speed cameras at speed 200f/s. Three dimensional coordinations for the anatomical landmarks was obtained through the DLT method. SPSS /PC⁺⁺ was used for the statistical analysis of the data. The result of kinematical analysis the flat service motion by means of three dimensional cinematography was as follows : 1. The motion execution time for the whole phase was 1.10±0.12s, with the motion execution time recored as fast as 0.11±0.01s, in the force production phase. 2. The maximum linear velocity of the racket was 30.98±1.25m/s, and at the point of impact, this linear velocity was recored as 29.25±1.50m/s. Also, the maximum velocity of the hand(14.56±0.49m/s) occured before(by 0.04s) the maximum velocity of the racket, and there was an efficient shift of power as the maximum velocity was recored in the consecutive order of the trunk, upperarm, lowerarm and the racket. 3. At the point of impact, the velocity of the tennis ball was 42.22±1.14m/s, the height of the toss 3.23m, the altitude of the impact 2.65m, and there was found to be no correlation between the velocity of the ball and the linear velocity of the racket at the point of impact. This was interpreted as the result of either the loss of energy in the body at the point of impact or discrepancies from using small number of study subjects. Also, the transition(X, Y, Z) of the center of gravity, from the minimal point to the point of impact, was recored as 44.5m/s, 29. 3㎝ /s and -6.l㎝ /s, respectively. 4. At the point of impact, the joint of the elbow showed the biggest change(169.9˚) of the joint angles, with the racket recording 133.3˚. Also, at 0.046s before impact, the minimum angle(138.4±5.852˚) was recored for the cocking angle, but by recording 167.6±6.93 at the point of impact, a change of approximately 29.2 was seen. 5. The maximum angle speed of each segment for the racket and the hand were recored as 53. 41±3.920rad/s and 39.87±4.915/s, respectly. 6. In the service motion the transition of power within the body occurred efficiently. However, consistent toss height of each subject and concentrated training of the first service is needed. Also, it was analyzed that there should not be a loss energy at the point of impact in order to have command of a stronger service.