Interior noise mainly comes from three aspects: engine noise, wind noise and tire noise. Noise reduction should start from these three points: first, reduce engine noise. Methods: With the different engine speed, the engine with sound absorption material under the hood produces noise, which is transmitted to the cab through the front fender, hood, firewall and exhaust pipe. Therefore, by stopping vibration and sealing these parts, the noise in the engine compartment can be effectively controlled and reduced. Second, reduce wind noise. Methods: The wind noise caused by installing sealing strip and door sound insulation is the noise caused by the friction between the rapid air flow and the car body during the car movement, that is, the noise caused by the air flow protruding the appearance of the car body or turning around in a dead corner during the driving process. Due to design reasons, the drag coefficient of automobile can not be changed, and it is difficult to remove it completely and effectively. The wind noise produced by different vehicles at different speeds is different (the wind noise begins to increase after the vehicle is generally accelerated to 100 km/h). Wind noise is introduced into the car through the gap in the door, so it can only be reduced by strengthening the sealing and sound insulation of the car. Third, reduce tire noise (road noise). Methods: 1, sound insulation materials were pasted on the door, the door edge, the upper part of the wheel arc, the fender and the chassis; 2. Change comfortable tires; 3. The radian of the soundproof cotton is attached to the front rear wheel cover.