Objective: To study the relationship between nutrition status and physical fitness in 8-10 year-old children in 3 cities, and to provide a scientific reference for improving physical condition of chidren of pre-school age. Methods: To investigate the weight, height and physical fitness (standing long jump, endurance running, rope skipping in one minute and sit-ups in one minute) of 1 384 children in grade four from 24 primary schools in Beijing, Changzhi, Urumchi in 2018. Evaluated overweight and obesity by using the standard of “Screening for Overweight and Obesity among School-age Children”. Then used mixed linear model to compare the physical fitness of students with different nutritional status and to analyze the relationship between BMI and physical fitness. Results: The prevalence of overweight and obesity were 17.41% and 23.48%, respectively. And the prevalence in boys was both more than that in girls(χ2=9.84，47.68，P<0.01). The increase in BMI of children from the same age and the same gender was related with the decrease in physical fitness by correlation analysis(P<0.05). In comparison method, the performance of the students of normal weight was better than obese students, but the male and female students had got the same results in their physical fitness test(P<0.05). Conclusion There is a negative correlation between nutrition status and physical fitness and the physical fitness in normal weight and obese children are better than the overweight children or obese children.