目的：分析國際網球總會（International Tennis Federation, ITF）青少年與國際職業網球協會 （Association of Tennis Professionals, ATP）選手之排名、年齡、比賽總場次與勝率。方法：從ITF 網站中4,488位同時擁有ITF與ATP最佳排名的選手，分析其ITF與ATP排名間之關係；並以單因子 變異數分析ATP前100名選手獲得ITF最高排名時平均年齡差異情形。結果：一、ITF排名前10名 選手能在ATP排名前100名的機率為31.75%。二、ATP前20名選手獲得ITF最高排名平均年齡顯著 低於ATP排名51-100名的選手。三、ITF排名前100名要有7成勝率，總場次需達106場；而ATP前 100名要有6成以上的勝率，總場次在650場以上。結論：越年輕取得ITF最佳排名的選手，越能 取得較佳ATP成績。ITF與ATP的排名會隨著勝場率與參賽總場次的增加而明顯上升。

Purpose: Analyze the ranking relation, player’s age, total matches played, and winning rates between ITF (International Tennis Federation) and ATP (Association of Tennis Professionals) players. Methods: 4,488 players with both ITF rankings and ATP rankings on the ITF website, and were analyzed to show the relations between ITF and ATP rankings. One-way ANOVA was employed to explore the average age of best ITF rankings and the differences between total games played and winning rate among ATP top 100 players. Results: 1. The probability of ITF top 10 players becoming ATP top 100 players was 31.75%. 2. The average age of ATP top 20 players who obtained best ITF rankings (age 17.66) was significantly lower than ATP top 51 to 100 players (age 17.94). 3. It required 70% winning rate and 106 games played in ITF; 60% winning rate and 650 games played in ATP to become top 100 players. Conclusion: The younger the players attained the best rankings; the more possible they obtained best ATP rankings. In addition, the rankings of ITF and ATP rose with winning rate. The rankings also went up with more games played after players entered the main draw.