Abstract: Objective To analyze breast milk compositions of lactating mothers in Longgang district of Shenzhen,so that to provide basic data for understanding nutritional compositions of breast milk and improving breast feeding quality.Methods A total of 14435 lactating women were recruited for this study. The nutritional compositions of their breast milk were detected and the detection results were analyzed statistically.Results The average content of fat,protein,lactose,energy,mineral and moisture was(4.25 ±1.77 g)/100 g,(0.996 ±0.14) g/100 g,(6.89 ±0.26) g/100 g,(69.77 ±15.10) kcal/100 g,(0.16 ±0.01) g/100 g and(87.71 ±1. 58) g/100 g. Among them,the highest abnormal detection rate was: higher fat(accounted for 21.80%),hither energy(10.47%),lower moisture(5.72%),and lower protein(4.94%). There was positive correlation between the content of fat and energy(r=0.997,P<0.01),and there were negative correlations between the content of fat and protein(r=-0.944,P<0.01),lactose(r=-0.322,P<0.01),mineral(r=-0.695,P<0.01) and moisture(r=-0.982,P<0.01).Conclusions The breast milk of lactating women in Longgang district showed higher fat and energy contents,and lower moisture and protein contents. The fat content in breast milk had correlation with protein、lactose、mineral、energy and moisture. It is necessary to detect nutritional compositions of breast milk to improve the diet of lactating mothers and provide basis for improving nutritional quality of breast feeding and further improving maternal nutrition and health status.