Objective To study the effectiveness and safety of Methazolamide (MTZ) in the treatment of patients with normal pressure hydrocephalus (NPH), to explore its mechanism of action, to enrich NPH treatment methods, and to broaden new ways of MTZ application. Methods A total of four cases of idiopathic normal pressure hydrocephalus (iNPH) and one case of secondary normal pressure hydrocephalus (sNPH) were collected from 2019 to 2020 in Aviation General Hospital, China Medical University. All iNPH patients met the diagnostic criteria of the 2005 International iNPH Guidelines. The five patients were all tested positive for a single lumbar puncture and were not suitable for or refused surgical treatment for various reasons. After obtaining the consent of the patient and their family members, they were given oral MTZ 25-50 mg, two times per day for treatment. The gait score, cognitive assessment, bladder function measurement, head MRI examination, iNPH grading score before and after oral MTZ were evaluated. After oral administration of MTZ, an improvement in iNPH score is greater than or equal to one point was defined as effective, and adverse drug reactions could be closely observed to evaluate the effectiveness and safety of MTZ on NPH. Results Among the five patients, four case were effective, including one case was slightly improved, and three cases were improved significantly (two patients with iNPH and one patient with sNPH), showed improvements in gait, cognition or bladder function. None of the five patients found clear MTZ-related adverse reactions. Conclusion MTZ may become one of the potential drugs for the treatment of NPH, but it still needs to be further confirmed by large randomized controlled trials.