Objective To investigate the current situation of growth and malnutrition across children under the age of 3 years in Jiangsu, and provide reference and evidence of improvement for children's healthcare during first three years in Jiangsu. Methods The research was based on a dynamic cohort of multi-center and large sample. The data was from the National Children Nutrition and Health Monitoring. Four monitored districts/counties in Jiangsu were selected, four communities (towns) from each district/county were chosen. Healthy children of permanent residence in these chosen communities (towns) under the age of 3 undergone the health monitoring from January 2016 to December 2019 were recruited as the research objects. Their monitored anthropometric data were analyzed, and compared with WHO growth standard. Weight and length (height) growth rates were analyzed and evaluated. Z score was employed for the evaluation of children's status of nutrition. Results A total of 43 518 healthy children under the age of 3 were recruited. The mean values of weight and length (height) of children at each age were all significantly higher than 2006 WHO standard (P<0.05). The weight and length (height) of males were all significantly higher than those of females at each age (P<0.05). The growth rates of males' weight before 8 months and length (height) before 6 months were all faster than those of females (P<0.05). The rates of underweight, stunting, emaciation, overweight and obesity of all children were 0.14%, 0.28%, 0.55%, 3.88% and 0.55%, respectively. The rates of underweight, stunting, overweight and obesity of overall males were all significantly higher than those of overall females (χ²=6.612, P=0.01; χ²=13.287,89.339, 18.732, P<0.001). Conclusions The status of growth during first three years are favourable but several types of malnutrition still exist in these 4 areas of Jiangsu. The prevalence of underweight, emaciation and stunting are all in low levels. However, overweight and obesity are still the significant issues in children's healthcare supposed to be paid attention in the future.