Depression is the most common mental illness in postpartum mothers, and the etiology of postpartum depression remains poorly understood. Over the past several decades, studies have reported that postpartum depression is caused by multiple factors, such as genetic, psychological, pregnancy, and environmental factors, with the family environment being an important environmental factor. The theory of family cohesion and adaptability put forward by Olson is a classic model that describes the level of family function. However, to date, this model has not been examined regarding its applicability to patients with postpartum depression. To investigate the relationship between family cohesion and adaptability and the risk of postpartum depressive symptoms. We retrospectively analyzed 1446 patients admitted to the postpartum healthcare clinic of the Affiliated Foshan Maternity and Child Healthcare Hospital from April 2021 to December 2021. Patients were grouped according to whether postpartum depression symptoms were reported (symptoms, n = 454; no symptoms, n = 992). All patients completed the Edinburgh Postpartum Depression Scale and the Chinese version of the Family Cohesion and Adapt-ability Assessment Scale II. Baseline and clinical data were compared between groups. Univariate regression analysis was used to investigate the association between different types of family cohesion and postpartum depressive symptoms and the association between different family adaptability types and postpartum depressive symptoms. After adjusting for age, education, occupation, gravidity, parity, and mode of delivery, disengaged [adjusted odds ratio (AOR) = 3.36, 95%CI: 1.91-5.91], and separated (AOR = 1.97, 95%CI: 1.34-2.90) family cohesion types showed a higher risk of postpartum depression than the connection type, whereas the enmeshed type (AOR = 0.38, 95%CI: 0.28-0.51) protected against postpartum depressive symptoms. Rigid (AOR = 4.41, 95%CI: 3.02-6.43) and structured families (AOR = 1.88, 95%CI: 1.34-2.63) had a higher risk of postpartum depressive symptoms than flexible families, whereas chaotic families (AOR = 0.35, 95%CI: 0.24-0.51) protected against postpartum depressive symptoms. Family cohesion and adaptability are influencing factors for postpartum depressive symptoms, with higher family cohesion and adaptability being associated with a lower risk of postpartum depressive symptoms.