The invention provides an automatic punching device of a car seat sliding rail, and belongs to the technical field of car production. The automatic punching device is used for achieving automation ofproduction of the car seat sliding rail. The automatic punching device is composed of a conveying support, a feeding support, a belt motor support, a reel motor support, a reel motor, a single membrane coupling, a reel support, a reel, a belt motor, a belt, a rolling wheel, a feeding rail, a punching mechanism, an edge cutting mechanism, an adjusting mechanism, bending mechanisms and a dischargingmechanism. According to the automatic punching device, a series of continuous stamping mechanisms are adopted, continuous, efficient and automatic stamping of the car seat sliding rail is achieved, feeding, machining and discharging are achieved through automation, errors caused by manmade factors are reduced to the minimum, stamping precision is guaranteed, and the labor cost is reduced. The work efficiency is improved, and meanwhile the mechanisms are simplified.