摘要Background A more comprehensive assessment of growth and nutrition in children is required in China due to rapid socio-economic processes.We aimed to investigate height and body mass index(BMI)trajectories from 1975 to 2015 and the prevalence of stunting and obesity in 2016 among children in Chinese cities.Methods A total of 904,263 children from birth to 6.9 years were collected from a series of nationally representative sur-veys in China.Height and BMI trajectories and prevalence of stunting,underweight,overweight and obesity were assessed.Results The average height level of Chinese urban children under 7 years presented a positive secular trend from 1975 to 2015;however,a slowing tendency occurred in 2005-2015.An apparent increase was observed at the 5th,50th and 95th percentiles of BMI in urban children aged 3 years and older,with a more prominent increase at the 95th percentile.The total prevalence of stunting and underweight under 7 years was 1.4％and 2.0％,respectively.The total prevalence of overweight and obesity under 7 years was 12.6％and 4.3％,respectively,with 12.7％and 4.9％for boys,12.6％and 3.6％for girls,12.1％and 4.0％in urban areas and 13.1％and 4.5％in suburban rural areas.Conclusions The average height level of Chinese urban children has reached World Health Organization child growth stand-ards since 2005 and presented a slowing tendency in secular trend in 2005-2015.More attention and efforts and public health interventions should be urgently made to combat overweight and obesity among preschool children.