Clazosentan therapy has been found to be effective in reducing the incidence of vasospasm after aneurismal subarachnoid hemorrhage (aSAH). The objective of this meta-analysis was to determine whether different doses of clazosentan treatment significantly reduced the incidence of delayed ischemic neurological deficits (DINDs) and new cerebral infarction (NCI). We systematically searched PubMed, Embase, Cochrane library and Medline from inception until October, 2015. All randomized controlled trials related to the functions of clazosentan in aSAH were included. Analyses were performed following the method guideline of Cochrane Back Review Group. Four randomized placebo-controlled trials met eligibility criteria and enrolled a total of 2159 patients. The meta-analysis demonstrated a significant decrease in the incidence of DINDs (relative risk, 0.49 and 95% CI, 0.33–0.73) and NCI (relative risk, 0.42 and 95% CI, 0.25–0.71) in patients treated with a high dose of clazosentan (15 mg/h) after aSAH. In addition, a high dose of clazosentan (15 mg/h) had no more effect on the incidence of adverse events than that of a low dose (1–5 mg/h). The results of the present meta-analysis show that a high dose of clazosentan significantly reduced the incidence of the vasospasm-related DINDs and NCI. Further study is required to fully understand the potential usefulness of clazosentan in patients with aSAH.