The team that scores more runs wins the baseball game. It indicates that a hitter possibly score once he gets on base. One of the biggest things for a pitcher in a ball game is to retire the hitters. No hitter reaches the base, no run is scored. According to the baseball rules, a hitter is out when a third strike is legally caught by the catcher. Therefore, the pitcher has a upper hand after the first strike. The researcher collected the official statistics of 11 pitchers on the Uni-Lions in 2014 CPBL Minor League games and took hypothesis testing to seek for potential significant difference between first pitch strike and first pitch ball in terms of on-base percentage. The results show that both starting pitchers and relief pitchers can lower down the on-base percentage by throwing first pitch strike, and that offers all pitchers a beneficial approach to practice and game, that is to say, to work ahead and throw first pitch strike.