Objective To gain a deeper understanding of the cognitive differences between lactating women and obstetric nurses regarding their breastfeeding counselling abilities.Methods This study was a descriptive phenomenology qualitative study.From October 2021 to June 2022,purposive sampling was used to select 11 lactating women who received breastfeeding counselling and 13 obstetric nurses who provided breastfeeding counselling services in Department of Obstetrics at Peking Union Medical College Hospital for semi-structured interviews.Giorgi analysis method was used to extract and analyze data.Results The cognitive differences between lactating women and obstetric nurses regarding breastfeeding counselling abilities were mainly manifested in four aspects,namely breastfeeding knowledge and skills,counselling practice ability,improving counselling ability,and personality traits.Conclusions Lactating women and obstetric nurses have cognitive differences in breastfeeding counselling abilities.Obstetric nurses should improve their breastfeeding counselling skills based on the needs of lactating women and provide personalized breastfeeding counselling services.