Abstract: Objective To analyze the age and gender differences and relevance between physical fitness and quality of life(QOL) in children and adolescents,and to provide bases for making appropriate intervention measures.Methods Totally 4 105 children and adolescents at age of 7-18 years in 4 cities of China were selected and the age and gender differences in physical fitness and QOL were analyzed.Results The ratio of boys with high score of physical fitness(27.2%) was significantly lower than that of the girls(35.2%).The ratio of high physical fitness score in boys and girls of high schools were the lowest(21.9%,26.8%).The scale of QOL of the boys(48.20±10.48) was lower than that of the girls(48.95±8.80).The scale of QOL of junior middle school boys and girls were the lowest(46.93±10.29,46.92±9.62).The scale of QOL of children and abolescents with high score of physical fitness(49.90±10.34) was higher than that of with moderate(48.79±9.92) and low scores(48.23±9.02) with statistical significance(P < 0.05).Conclusion There are differences between age and gender groups in physical fitness and QOL in children and adolescents.There is a close correlation between physical fitness and QOL among children and adolescents.