Children with autism spectrum disorder (ASD) frequently have comorbid gastrointestinal problems, with constipation being the most prevalent. The onset and severity of constipation are closely related to the core symptoms of ASD, and improving constipation can alleviate these core symptoms. However, the mechanisms underlying comorbid constipation in ASD remain unclear. Multidisciplinary assessment is the foundation of clinical management for comorbid constipation in ASD. Targeted pharmacological therapy, dietary interventions, gut microbiota modulation, and complementary and alternative medicine interventions can be chosen for personalized treatment. This review summarizes the mechanisms, assessment, and clinical management of comorbid constipation in ASD and aims to provide a reference for comprehensive interventions in ASD.