The invention discloses an automatic lifting mechanism for digital image equipment suitable for traffic investigation. A bracket of the automatic lifting mechanism has an equilateral octagonal semi-opened structure; a driving arm and a driven arm are fixed below the bracket; a self-locking device is fixed on the inner side of the bracket; a mechanical arm holder and a balance arm are fixed above the bracket; an electric control device and a battery are fixed below the mechanical arm holder; an elastic part, a roller and a rubber rib tire are arranged on the driving arm, the driven arm and thebalance arm; the roller is tightly attached to a guide rod; the driving arm drives the mechanism to do continuous linear motion along the guide rod, and the driven arm helps the driving arm; the self-locking device fastens the mechanism at any position on the guide rod; the digital image equipment is fixed on the mechanical arm holder, and a shooting angle can be adjusted; the balance arm can counteract a moment produced by the mechanical arm holder; the electric control device is powered by the battery; and a remote controller remotely controls the driving arm, the self-locking device and the mechanical arm through the electric control device. The automatic lifting mechanism has a simple structure, is convenient to operate and carry, and can be widely applied to traffic investigation.