Objective To describe secular trends on physical growth of children in China during the year of 1985-2005 and to analyze the urban-suburban-rural difference and its change.Methods The measurements of height, weight and chest circumference obtained from two serial national cross-sectional surveys for children aged 0 to 7 years in China were used to analyze the secular trends, and the growth differences among urban, suburban and rural children were compared.Results The average weight and height for both boys and girls from urban, suburban and rural areas have significantly increased in most age groups during the past 20 years; The average chest circumference increased slightly, ranging from 0.0 to 2.0 cm. From 1985 to 2005, the urban-suburban difference in height had become smaller, and that in weight showed similar trend for children under 3years old but became larger after 3 years old; the suburban-rural difference both in height and weight became larger after 6 months old. The increment per decade in height was the greatest in the suburban group while the greatest increment in weight was the urban group.Conclusion Positive secular trends were observed among urban, suburban and rural areas in Chinese children under 7 years old during the 1980s and the 2000s, reflecting a rapid socio-economic development in China.