Breast milk is a perfect food for infants; however, the rate of exclusive breastfeeding is low. The relationship between exclusive breastfeeding practices and influencing factors is complex and remains unclear. This cross-sectional study was conducted in Changsha County, China, and 414 mothers were enrolled. An online questionnaire was used to collect data on general information, obstetrics and gynecology characteristics, the initial breastfeeding intention, breastfeeding practice, frequency of attending conventional breastfeeding programs before delivery, the status of breastfeeding self-efficacy, and the status of perceived social support. Structural equation modeling (SEM) was used to estimate the association between exclusive breastfeeding and potential risk factors of failing to practice exclusive breastfeeding for 6 months. The rate of exclusive breastfeeding for 6 months was 46.1%. The median and interquartile range of the scores for breastfeeding self-efficacy and perceived social support were 51.0 (18.0) and 68.0 (20.0), respectively. Factors that were statistically significant in the univariate analysis were included in the SEM and model fitness was acceptable based on the results. Exclusive breastfeeding for 6 months was directly associated with intention and self-efficacy, while it was indirectly associated with perceived social support and frequency of attending a breastfeeding program. The findings support the recommendation that comprehensive breastfeeding promotion strategies should be implemented to call on the intention and self-efficacy of breastfeeding mothers through various measures, such as education or providing medical and health services.