Children’s physical fitness is an essential indicator of their health status and，to some extent，a direct reflection of the physical fitness of the nation population. The effective enhancement of children’s physical fitness is one of the most important ways to improve health throughout the life cycle. In recent years，the physical fitness of children aged 7-18 in China has seen both improvements and shortcomings. Using the data from 2010，2014 and 2019 Chinese National Surveys on Students’ Constitution and Health （CNSSCH），this study assessed the trends of physical fitness components in Chinese children aged 7-18. The findings showed that there was an improvement in flexibility while a decrease in lower limb explosive strength；the speed qualities showed an overall downward trend but improvement was seen in girls and secondary school students；the body muscle strength increased for girls and primary school boys but continued to decline for secondary school boys；as for endurance，there was a general downward trend，but an improvement among secondary school students. Therefore，it is important for current research on the health of children and adolescent to identify and analyse influential factors for the changes of physical fitness and propose targeted recommendations from the aspects of national policy，school，family，social support，and individuals to improve child physical fitness.