The utility model relates to an exposure part of a digital photo processor, in particular to an exposure and paper feeding device of a digital photo processor, which comprises an exposure mechanism and a matching paper-feeding roller device. The utility model is characterized in that the exposure mechanism adopts a three-color semiconductor laser as a light source. The laser rays shine along the axis direction of a roller onto a piece of reflective mirror (7) driven by a small precision motor (5) rotating with high speed and is reflected to the roller wall perpendicularly, at the same time, a support bracket of the motor can move straightly along a precision linear guide (3) driven by a precision lead screw (4), thus the laser rays can form a spiral lattice on the inner surface of the roller wall (i.e. exposes the printing paper). The paper-feeding roller device comprises an arc-shaped paper-feeding conveyor belt (11). A guide device is arranged between the two ends of the conveyor belt (11) which can cause the printing paper to move towards the farther end of the conveyor belt when the printing paper is fed into or sent out from the machine, thereby reducing effectively the degree of bending of the printing paper and eliminating the need of a complex auxiliary mechanism, so that the utility model can be simple and reliable with low failure rate.