Objective To summarize the clinical features, diagnosis and treatment methods of cervical necrotizing fasciitis (CNF) combined with descending necrotizing mediastinitis (DNM). Methods Medical records of 6 patients with CNF combined with DNM and treated in the Second Affiliated Hospital of Kunming Medical University from January 2015 to May 2020 were analyzed retrospectively. Results Six patients all underwent neck debridement and drainage in the early stage, 2 of whom underwent thoracoscopic mediastinal incision and drainage, 1 underwent chest wall debridement, and 5 underwent tracheotomy due to dyspnea caused by tracheal compression. After operation, antimicrobial use was adjusted according to antimicrobial susceptibility testing results, patients continued anti-infection and nutritional support, actively treated underlying diseases, rinsed the wound every day, strengthened dressing change, and performed debridement once and 4 times in 2 cases respectively. All 6 patients had fever, as well as symptoms of neck and chest during disease course, which progressed rapidly. Infection indicator procalcitonin (PCT) and C-reactive protein (CRP) were both high, multiple honeycomb pneumatosis ("bubble sign") in the neck was found through neck thoracic CT, and extended to the mediastinum. 3 cases were cured and 3 cases died. The cured cases were followed up for 1-4 years and recurrence was not found. Conclusion The "bubble sign" showed by neck and chest CT is the "gold standard" for early diagnosis of CNF combined with DNM, the key to cure the disease lies in early diagnosis, timely surgical debridement and drainage.