Background Functional constipation (FC) is a common health problem in children and a high frequency of consultations among parents of children in outpatient clinics of primary medical and health institutions. Although constipation is not an emergency, it may cause serious complications if not managed properly, which then can affect the quality of life of children and their families. Objective To understand the capacity of primary-level doctors' diagnosis and treatment in children's FC, and provide a basis for improving primary-level doctors' capacity of diagnosis and management of children's FC. Methods In July 2020, 130 doctors who had access with children's patients in their daily diagnosis and treatment were selected from primary-level medical and health institutions in Xicheng District, Beijing. A self-designed questionnaire from our research group was administered to the included physicians. The content included awareness of the common symptoms of FC diagnosis for children ≥6 months of age, and the recommended treatment methods, recommended treatment drugs, medication timing and treatment duration for children with FC. Results Questionnaires from 108 (83.1%) basic medical doctors were validly returned, including 34 (31.5%) from general practitioners, 30 (27.8%) from pediatricians, 30 (27.8%) from traditional Chinese medicine doctors, and the average monthly outpatient volume with pediatric patients (10.1±4.4) cases was obtained. For the diagnosis of FC in children: when children aged ≥6 months presented with less frequent bowel movements, hard stools, bleeding during defecation, fecal incontinence, difficulty in defecating, and crying symptoms before passing thick stools, 40.7% (44/108) , 39.8% (43/108) , 23.1% (25/108) , 9.3% (14/108) , 39.8% (43/108) , 23.1% (25/108) of the basic medical doctors would consider the diagnosis of FC; 51.9% (56/108) of the physicians considered FC to be diagnosed when two symptoms, including low frequency of defecation and difficulty in defecating, existed simultaneously; according to 25.0% (27/108) of the physicians, FC can be diagnosed when four symptoms including less frequent defecation, hard stools, bleeding during defecation, and difficulty in defecating were present at the same time. For the treatment of FC in children: pharmacotherapy was recommended as the main treatment of choice for FC in children by primary physicians in 37.0% (40/108) ; nonpharmacologic therapy was recommended as the preferred treatment by 63.0% (68/108) of the primary physicians, with 88.2% (60/68) recommending abdominal massage, 85.3% (58/68) recommending a high fiber diet, 82.4% (56/68) recommending toilet training, and 72.1% (49/68) recommending increased fluid intake. Lactulose therapy was recommended by 75.9% (82/108) of the primary physicians; 27.8% (30/108) of the primary physicians recommended combination therapy with microenemas of sodium citrate, sodium dodecylsulfonylacetate, and sorbitol as the rectal treatment, and 64.8% (70/108) of the primary physicians recommended rectal administration when children had particularly difficult bowel movements. According to the basic medical practitioners, the mean time from initiation of treatment to having a positive response was (4.1±2.6) days in children; the mean treatment duration of FC in children by primary physicians was (21.2±4.3) days; 88.9% of doctors believed that the average termination time of constipation treatment was (46.0±9.3) days. When the frequency and/or consistency of bowel movements returned to normal or the patient no longer had discomfort, 88.9% of physicians responded that they would consider discontinuing the treatment. Conclusion Although general primary doctors know some methods of diagnosis and treatment of children's constipation, their overall level of awareness still needs to be improved. It is recommended to further enhance the existing primary physicians' awareness and comprehensive management of FC in children, and to develop a comprehensive management model of FC in children in primary health facilities to improve the management level of children's functional constipation, thereby reducing the prevalence and increasing the cure rate.