The purpose of study was to investigate the development of the Health-Related Physical Fitness of elementary school students in six municipalities. The researcher used SPSS (Statistical Packages for Social Science) Version 22.0 to analyze the quantitative data. To explore the significant differences of the Health-Related Physical Fitness in genders was used Descriptive statistics and one-way ANOVA were used to probe the differences of the Health-Related Physical Fitness in grades , the size of the schools and different municipalities. The findings of the present study were as follows. 1. There were four elements in the health and fitness of elementary school students that will increase as they get older, including explosive strength, muscle strength and muscular endurance, cardiorespiratory endurance and body mass index. In addition, the flexibility factor gradually decreases with the age. 2. According to the comparison among the six municipalities, the findings indicated that (1)the muscle strength and cardiorespiratory endurance of elementary school students in Taipei and New Taipei City were significantly better, (2) the softness of elementary school students in Taoyuan City was significantly better, (3) the softness of elementary school students in Taipei City School was significantly worse, (4) The cardio-respiratory endurance of elementary school students in Tainan City Elementary is poor and the muscular endurance of elementary school students in Kaohsiung City is poor. The instant force and body mass index (BMI) were not significantly different. Overall, the fitness performance of students in Taipei City and New Taipei City was better.