The invention discloses an automatic control system for compaction density of a pole piece. According to the system, the coated pole piece passes through a rolling production line, production is controlled by a rolling production line control system, the surface density of the pole piece is detected by a double-face penetration type beta sensor, the thickness is detected by a double-face laser sensor, detection data is transmitted to the rolling production line control system via a data transmission network, the pole pipe is rolled through rolling rollers, a servo control system is installed on the rolling rollers for controlling the roller gaps, and a position detection sensor is installed on the rolling rollers for detecting the actual roller gap. The automatic control system for compaction density of the pole piece is simple in structure and reasonable in design, reduces artificial intervention on regulating of pole-piece rolling degree, and realizes automatic regulation, reduces the regulation hysteresis phenomena on pole-piece thickness and compaction density during production, realizes automatic stable controlling on compaction density during rolling of the pole piece, and is relatively intelligent. A novel rolling method for the pole piece is provided, and the control manner on pole-piece rolling production is expanded.