This study was planned to compare the difference of the service return following the frist service and second service in the tennis game. 3 dimensional motion analysis was done at \'primary school men\'s single games\'. The athlete-movement and ball-movement was recorded. The analysis of the game was done based on the taken video. Also the speed of the first serve and second serve, speed and angle of the service-returned ball, absolute/relative position of the returned ball and the distance of the receiver movement were analysed. The study was done with 3 tennis players who are all in the 5th grade of a primary school. Here is the conclusion through the analysis of the game and data. According to the condition analysis, the server\'s incidence of making an error after the first serve was higher than that after the second serve. It\'s considered to be due to the fact that first serve is usually faster and also wider in angle. So that it\'s harder for the receiver to hit the ball in the proper place. Service-ace rate was higher for the first serve than the second serve. The possibility of making a score was slightly higher for the second serve than the first serve. According to the motion epidemiology analysis, the following was found. 1) The speed of the first service was higher than the second. And the speed of the service return was lower following the first serve compared to the one following the second serve. This highlights the importance of the first serve. 2) The angle deviation of the service-returned ball was greater following the first serve compared to that of the second serve. This implies the that the faster and more powerful first service tends to interrupt the receiver more from having the right racket angle at the moment of hitting the ball than the slower and weaker second serve. 3) According to the absolute position analysis, the first-service-returned ball fell further from the end-line of the server\'s court. And the distance server moved(back and forth, left and right) to reach the service-returned ball was longer after the first serve than the second server. 4) According to the relative position analysis, the place where the service-returned ball hit the court was further from the midpoint of the server\'s both foot with first serve compare to that of the second serve. This implies that the unstable returns tend to follow more with the first service compare to the second serve. Which also means the returner could not have the stable impact position that is inevitable for the aggressive return.