The sound induced by a closing door is determined by the various components like door latch, door module, door glass installed within the door area. The key components vibrate due to the force from the closing door, and the combined vibration caused by the components determines the sound from the door. In particular, when the door is closed with the door glass down, the vibration and noise of the door glass are louder than those of any other component; this is called door glass rattle - attributed to the loss of the door glass support point. This study not only evaluates the rattle influence level of a door glass support but also introduces an approach to reduce glass rattle noise by using sealing components. 1. Study on Minimization of Vibration A jig was constructed to evaluate the level of influence of the rattle of a door glass support. The frequency response obtained via impact hammer testing was analyzed by varying the glass support points; important factors that should be considered in the early design stage were obtained. 2. Study on the Optimization of Vibration Absorption A glass run, D/S W/STRIP, B/S W/STRIP were used to absorb vibration. 2-1 Optimization of Glass Run Vibration Absorption The glass run section was created through the TRIZ technique. The performance evaluation of the rattle in the section showed that the damping speed improved by 35% compared with the damping speed of the existing glass run, rendering it possible to significantly reduce glass rattle noise. 2-2 Vibration Absorption by W/STRIP This study suggested an approach to reduce both the vibration caused by DR BIW and door glass rattle noise by using weather strips. This study also showed that D/S W/STRIP was the most useful in reducing rattle noise.