Abstract: To reveal the hydrodynamic mechanisms underlying the superior tar reduction performance and distinct smoking experience of grooved filter cigarettes, the velocity fields, smoke retention times, and local vortex structures of conventional and grooved filter cigarettes were studied by simulation using computational fluid dynamics (CFD) methods. Subsequently, the velocity distribution at the outlet of the filter obtained by simulation was used as the inlet condition to analyze the flow and deposition behavior of the smoke inhaled by the two types of filters in oropharyngeal region. The results show that: 1) As the radial smoke continuously flows into the grooves, from the inlet of the grooves to the suction end outlet, the proportion of the smoke flow rate within the grooves increases from 23.60% to 77.64%. 2) The vortices formed at the entrance of the groove facilitate the rapid mixing of the smoke and ventilation air flow when they enter the grooves, and also result in a longer average residence time of the smoke and a greater variance in the residence time distribution for the groove filter cigarettes. 3) The smoke with higher velocity inhaled through the groove filter into the oropharyngeal region directly impacts the upper surface of the throat and forms a reflux that diffuses throughout the entire oral area, thus, the deposition amount on the tongue surface is less than that of conventional filter cigarettes.