The invention discloses a carbon fiber rod automatic tensioning device. The automatic tensioning device comprises a pedestal, a frame, driving wheels, pinch rollers, a pressure sensor, a pinch roller adjusting mechanism and a servo motor. The automatic tensioning device is characterized in that the frame is connected with the rails of the pedestal; the driving wheels are arranged on the frame and driven by the servo motor; the pinch rollers are arranged on the frame and arranged to be opposite to the driving wheels; the pressure sensor is arranged at the front end of the pedestal and arranged to be opposite to the front end plate of the frame; a wire passing hole for passing of a carbon fiber rod is arranged in the front end plate of the frame; the servo motor adjusts a rotating speed through a feedback signal of the pressure sensor. Through direct sensing of a dynamic tensile force of the carbon fiber rod, the feeding speed of the carbon fiber rod is controlled accurately, the condition that the tensile force of the carbon fiber is within a standard scope is ensured, and reeling quality is ensured.