The car brake assist unit includes the electronic brake assist system “EBA” (Electronic Brake Assist) and the brake force assist system “BA” (also known as “BAS”) “Brake Assist Syste”, which refers to the ability to judge the braking action of the driver ( Strength and speed), increase the braking force during emergency braking, thereby shortening the braking distance. For drivers like the elderly or women whose ankles and legs are not very strong, the advantages of this system will be more obvious. The mechanical brake assist system "BA" is actually the predecessor of the electronic emergency brake assist system "EBA". This braking force auxiliary unit includes the current vacuum booster unit, electric booster unit and hydraulic nitrogen booster unit to achieve the auxiliary effect of braking force through these methods. Air is sent to the spring and shock absorber air chamber to change the height of the vehicle. There is no vehicle height sensor near the front and rear wheels. According to the output signal of the vehicle height sensor, the microcomputer judges the change of the vehicle height, and then controls the exhaust valve of the compressor to compress or extend the spring to reduce emissions. The effect of vibration.