The purpose of this study was to investigate whether the tennis service elements were played as a key to be a winner at the game. Also, this study investigated what kinds of service abilities a successful tennis player should possess and how those abilities were enhanced. The performances of the top 15 professional tennis players in World Tennis Association (WTA) around the world were used to study whether the determination of the world-ranking were related to the most ace amount, and what percentage of the successful first serve of the top 15 professional tennis players got. In addition, this study also proposed several methods to enhance players’ service abilities. The conclusions were as followed: 1.Good tennis player must have abilities to (1) serve fast ball, (2) serve different types of curve ball, and (3) control the ball with high stability. 2.Methods that we suggest to promote the ability of tennis service include: (1) improving serve speed: increasing the height of stroke, adopting a lengthened racket, and using stroke mechanics for body control; (2) serving the curve ball: serving different types of curve balls, and serving the same type of curve ball with different speed; and (3) serving the ball with more stability: choosing proper serving position, and enhancing serve accuracy.