Abstract: To study the hydrodynamic mechanisms behind tar reduction performance and distinct smoking experience of grooved filter cigarettes, the velocity fields, smoke retention time and local vortex structures of conventional and grooved filter cigarettes were studied by computational fluid dynamics (CFD) simulation. Subsequently, the velocity distribution at the outlet of the filter obtained by the simulation was used as the input condition to analyze the flow and deposition behavior of the smoke in the oropharyngeal region of the respiratory tract. The results showed that: 1) As the radial smoke continuously flowed into the grooves, from the inlet of the grooves to the puffing end outlet, the proportion of the smoke flow rate within the grooves increased from 23.60% to 77.64%. 2) The vortices formed at the inlet of the groove facilitated the rapid mixing of the smoke and the ventilation air flow and also resulted in a longer average retention time of the smoke and a dispersed distribution of residence time for the grooved filter cigarettes. 3) The smoke velocity inhaled through the grooved filter into the oropharyngeal region was higher, directly impacting the upper surface of the throat and formed a reflux that diffused throughout the entire oral cavity, resulting in a lower amount of smoke deposition on the tongue surface compared to conventional filter cigarettes.