Currently the powerful nation of badminton in the world are monopolized by some countries of Middle-South Asia, drawing on the experience of successful reform of table tennis, the 21 points new scoring system of badminton comes shining through. In this paper, it uses the classical probabilitymodel to establish a functional relationship between thewinning probability of single round and the winning probability of single game, through observation, and uses hyperbolic tangent curve fitting method to simplify the expression, and thus leads to the indicators of the game time. By calculating the distance of each evaluated object separately to the ideal and non-ideal solution, coupled with the comparison, the comprehensive evaluation of four different competition systems are obtained. However, there is no absolute advantage or disadvantage for each competition system. Therefore, in the evaluation process, this paper uses the relative analysis and comprehensive evaluation methods to analyze the four options given in the title. The outcome is that the best of three innings for 21 points systemand the best of five innings for 15 points systemaremore reasonable competition system.