Road　roughness　is　a　significant　index　to　evaluate　driving　comfort　and　safety.　However,　the　evaluation　commonly　used　both　in　China　and　abroad　shows　great　subjectivity　due　to　the　lack　of　information　about　passengers＇　physiological　responses.　To　make　evaluation　more　objective　and　comprehensive,　this　research　analyzes　the　change　of　various　physiological　indexes　on　different　roughness　conditions.　The　result　indicates　that　road　roughness　has　a　definite　impact　on　physiological　indexes　and　there　is　a　logarithmic　relationship　between　the　range　of　heart　rate　and　the　average　of　international　roughness　index　(IRI),　which　shows　that　it　is　reasonable　to　use　the　combination　of　IRI　and　heart　rate　to　reflect　road　comfort　and　safety.