The flow between a grooved and a flat plate was presented to investigate the effects of groove on the behavior of hydro-viscous drive.The flow was solved by using computational fluid dynamics (CFD) code,Fluent.Parameters related to the flow,such as velocity,pressure,temperature,axial force and viscous torque,are obtained.The results show that pressure at the upstream notch is negative,pressure at the downstream notch is positive and pressure along the film thickness is almost the same.Dynamic pressure peak decreases as groove depth or groove number increases,but increases as output rotary speed increases.Consequently,the groove depth is suggested to be around 0.4 mm.Both the groove itself and groove parameters (i.e.groove depth,groove number)have little effect on the flow temperature.Circumferential pressure gradient induced by the groove weakens the viscous torque on the grooved plate (driven plate) greatly.It has little change as the groove depth increases.However,it decreases dramatically as the groove number increases.The experiment results show that the trend of experimental temperature and pressure are the same with numerical results.And the output rotary speed also has relationship with input flow rate and flow temperature.