Objective To measure the normal cerebrospinal fluid of the midbrain aqueduct peak velocity of different age groups by using magnetic resonance imaging (MRI) time‐spatial labeling inversion pulse (time‐SLIP) ,and to discuss the flow law of CSF . Methods Forty‐one cases of healthy volunteers ,including 23 cases of male ,18 cases of female ,aged 7 -73 .Patients were divided into 4 groups:7- <15 age group (n=11) ,15- <35 age group (n=10) ,35- <45 age group (n=9) ,≥45 age group (n=11) .We used the application of Toshiba 1 .5 T MRI head coil ,MRI sequence of time‐SLIP marked CSF to calculated the peak velocity of CSF in the midbrain aqueduct and measure the diameter and length of the midbrain aqueduct .Results The peak flow velocity be‐tween the 7- <15 age group and 15 - <35 age group ,35 - <45 age group ,≥45 age group were statistically significant (P<0 .05);inner diameter and length were no statistically significant difference (P>0 .05) between age .Conclusion In the midbrain aqueduct ,CSF is two‐way flow and supports the CSF of the pulsatile flow theory ;MRI sequence of time‐SLIP could measure CSF velocity and display the turbulence fluiding .