The invention belongs to the technical field of automobile brake mechanisms, and particularly relates to an automobile brake mechanism based on thread transmission. The automobile brake mechanism comprises a fixed arc plate, a brake trigger mechanism, a plurality of heat dissipation holes, a brake disc, a mounting hole and a T-shaped groove, wherein the through heat dissipation holes are formed inthe end face of the brake disc, the end face of one end of the brake disc is fixedly arranged on the end face of a drive shaft, and a first accommodating cavity is formed in the inner circular surface of the fixed arc plate. According to the automobile brake mechanism based on thread transmission, a brake pad worn by the light brake is different from a brake pad worn by the strong brake, when thelight brake fails, people can realize the need to replace the brake pad, and continue to drive safely by using the strong brake. In addition, when the brake pad is installed, the working surface of the brake pad can be equipped with a slightly-lower-quality brake pad during the light brake, while the working surface of the brake pad can be equipped with a higher quality brake pad during the strong brake, so that the safety of whole vehicle braking is improved, and at the same time, the economy is guaranteed. The economy can be guaranteed while a goal of car safety can be taken into account.