Abstract: Objective To investigate the cerebral vasoreactivity in patients with lacunar stroke and influencing factors. Methods Total 75 cases of acute lacunar stroke were consecutive selected in our hospital between January,2014 and January,2015. Sixty healthy cases with matched age and sex were selected as control. Detailed clinical data and imaging features were recorded in patients with lacunar stroke. The degrees of leukoaraiosis were measured by Fazekas scale classification. The Mean flow velocity(MFV) and breath holding index(BHI) were calculated by the transcranial Doppler(TCD) breath-holding test in patients with lacunar stroke and the control group. Further analysis of the influence of clinical related factors to BHI was performed in lacunar stroke patients. Results The based MFV[(56. 5 ±8. 9) cm/s] and BHI(1. 09 ±0. 18) were lower in lacunar stroke patients than those in the control group[MFV:(59. 9 ±6. 6) cm/s;BHI:1. 39 ±0. 14],the difference was statistically significant(P < 0. 05); The degrees of leukoaraiosis was negatively correlated with BHI in lacunar stroke patients(r=- 0. 869,P < 0. 01). The lower the BHI score was correlated with the higher grades of Leukoaraiosis. The multivariate linear regression analysis showed that age(OR=- 0. 333,P < 0. 01) and degree of leukoaraiosis(OR=- 0. 583,P < 0. 01) were the risk factors for BHI in lacunar stroke patients. Conclusion The vascular reactivity in lacunar stroke patients is commonly severe destroyed,and cerebral blood flow regulation function is severely impaired; The more severe white matter damage,the more severe vasoreactivity injure. Age and grade of leukoaraiosis are risk factors for the cerebral vasoreactivity in patients with lacunar stroke.