Objective Observation of Posterior decompression dural enlargement repair + Resection of the cerebellar tonsils and Posterior decompression dural enlargement repair two operation method for treatment of Chiari Ⅰ malformation effect.Methods Retrospectively analyze the clinical data from Jan.2006 to Jun.2012,the department of Neurosurgery,People's Hospital of Xinjiang Uygur Autonomous Region for a total of 97 cases of Chiari Ⅰ malformation.Group A was performed in 55 cases for Posterior decompression dural enlargement repair + Resection of the cerebellar tonsils,group B was performed in 42 cases for Posterior decompression dural enlargement repair,and was compared of the effect of the operation,Syringomyelia resolution and the rate of postoperative complications.Results Outpatient follow up for 6 months-8 years,a total of 85 patients were followed up for.According to the criteria of Tator,A,B two groups in the superior,good,poor rate was no significant difference (P ＞ 0.05).Promote syringomyelia regression had no significant difference(P ＞ 0.05).A,B two groups of postoperative incision infection were 5 cases and 4 cases,Postoperative transient headache were 25 cases,18 cases.Early postoperative cerebrospinal fliud leakage and subcutaneous effusion were 8 cases,6 cases.One cases died in group A.The total complication rate had no significant difference (P ＞ 0.05).Conclusions Posterior decompression dural enlargement repair + Resection of the cerebellar tonsils and Posterior decompression dural enlargement repair both are the treatment of Chiari Ⅰ malformation and reliable method.No significant difference exists between the effects of two operation,while the posterior decompression dural enlargement repair operation steps to reduce the damage.