Objective To investigate the clinical effect of small-incision micro-bone window atlantooccipital decompression combined with atlantooccipital fasciolysis in the treatment of Chiari malformation type I， as well as the stability of atlantooccipital junction after surgery.Methods A total of 31 patients with Chiari malformation type I and dizziness who underwent small-incision micro-bone window atlantooccipital decompression combined with atlantooccipital fasciolysis in our hospital from January 2012 to December 2017 were enrolled. The treatment outcome was evaluated according to the Chicago Chiari Outcome Scale （CCOS）， and the patients were followed up for 3~6 years after surgery to observe the stability of atlantooccipital junction.Results All patients underwent a successful surgery， with no death or serious complications including neurological dysfunction. Repeated evaluation of CCOS score at 1， 3， 6， and 12 months after surgery obtained a total mean score of 13.56， and among these patients， 24 （77.4%） had good prognosis， 5 （16.1%） did not have marked improvement， and 1 （3.2%） had poor prognosis. After 3~6 years of follow-up， the rate of dizziness relief was 93.5%； of all patients， 30 had a stable atlantooccipital junction， and 1 patient with atlantoaxial dislocation experienced the aggravation of symptoms after 1 year and required internal fixation.Conclusions Small-incision micro-bone window atlantooccipital decompression combined with atlantooccipital fasciolysis is safe and effective in the treatment of Chiari malformation type I， with simple operation and few complications， and there is also a high rate of dizziness relief. Long-term follow-up shows that the atlantooccipital junction remains stable. ［Citation:Journal of International Neurology and Neurosurgery, 2021, 48(4): 370-373.］