Objective: To discuss the function of lumbar cerebrospinal fluid drainage,LCFD,in the treatment of patients received decompressive craniectomy.Methods: The 62 TBI patients received decompressive craniectomy were divided into two groups,sustained LCFD with 35 cases and given routine dehydration treatment with 27 cases,each group recorded their courses of disease and analyzed their prognosis.Results: All the 35 patients received good clinical prognosis without adverse effects.There are 2 deaths and 4 cases of cerebrospinal fluid leakage in 27 patients of the control group.Conclusions: LCFD is a safe treatment for drainaging bloody CSF and decreasing intracranial hypertension.It is worthy for spreading with its good clinical effects.