Objective To explore the status of breastfeeding and complementary feeding of infants and toddlers at 6 and 12 months of age， and to analyze the related influencing factors to inform interventions for breastfeeding and complementary feeding problems in infants and toddlers.

Methods A total of 910 children selected from Pudong New Area of the Shanghai maternal-child pairs cohort， who completed follow-up at 6 and 12 months of age， were included in the study. A feeding status questionnaire completed by the parents was used to understand the breastfeeding and complementary feeding status of children at 6 and 12 months of age， and correlation analysis was conducted between the breastfeeding and complementary feeding status and the influencing factors.

Results The breastfeeding rate of infants at 6 months was 76.2% （693/909）， with a higher rate among girls than boys， and the rate of continuous breastfeeding at 12 months was 35.5% （322/906）. The minimum dietary diversity （MDD） pass rate at 6 months was 16.1% （146/906）， higher in boys than in girls （χ² =5.384， P<0.05）. The MDD pass rate at 12 months was 61.6% （554/899）. The likelihood of MDD failure in 6-month-old boys was 1.499 times higher than that in girls. Feeding of oils and their products， beverages （fruit juices）， and snacks （chocolates， candies， cakes， cookies， etc.） were risk factors for MDD failure in 6‒ and 12‒month-old children. Compared with no intake of oils and their products， beverage and snacks， the OR （95% CI） for MDD failure in 6-month-old infants fed with oils and their products， beverage and snacks were 5.866 （2.496‒13788）， 4.542 （2.943‒7.010）， and 2.599 （1.243‒5.261）， respectively. Compared with the non-fed group， the OR （95% CI） of MDD failure in infants aged 12 months fed with oils and their products， snacks， and sweet drinks were 2.335 （1.736‒3.140）， 1.549 （1.107‒2.168）， and 1.485 （1.116‒1.976）， respectively （P<0.05）.

Conclusions The rate of continuous breastfeeding in children at 12 months in the Pudong New Area of Shanghai is low， and the dietary structure of children is unreasonable. Improvements are needed in the introduction of complementary foods. Unhealthy foods such as oils and their products， beverages， and snacks are all high-risk factors for MDD failure in children at 6 and 12 months.