Childhood obesity has increased rapidly in China, but understanding is limited on how parents perceive their child’s weight status and how this perception affects weight-related parenting practices. We examined maternal perception of her child’s weight status and its association with demographics, subsequent weight-related parenting practices, the child’s health behaviours and weight change.

Maternal perception of child’s weight status and health behaviours from the China Health and Nutrition Surveys were assessed at baseline and in follow-up surveys for 816 children aged 6–18 years during 2004–2011. Associations were tested using mixed models.

Overall, maternal and child perceptions of the child’s weight status were fairly consistent (κw=0·56), 63·8 % of mothers had correct perception. While 9·6 % of mothers perceived their child as overweight, 10·9 % of children did so, and 13·6 % of children were indeed overweight. Compared with mothers who viewed their children as normal weight, mothers who thought their children were overweight were more likely to encourage their children to increase their physical activity (OR; 95 % CI: 1·8; 1·0, 3·3) and to diet (4·3; 2·3, 7·8). Children perceived as overweight by their mothers were more likely to have insufficient physical activity (2·8; 1·6, 4·7) and gain more weight during follow-up (BMI Z-score, β (se): 1·0 (0·1); P<0·01) than children perceived by their mothers as normal weight.

In China, mothers who perceive their child as overweight are more likely to encourage their child to exercise and modify their diet for weight management, but this encouragement does not seem to improve the child’s health behaviours and weight status.