A cutting and dust or slurry collecting assembly that comprises: a circular saw blade (4), a blade guard (5), a cover device (6), a discharge member (52) and a connection member (12), wherein the blade guard and the cover device (6) are connected in an pivoted manner through a hinge (40) or can be connected to each other; the hinge is arranged in the relatively lower relief angle of the blade guard or is adjacent to the rear, so that the cover device and the blade guard can rotate relative to each other to enable the saw blade (4) to move up and down in the passage (45, 46) during the cutting process; the discharge member (52) is arranged at the rear of the hinge and is provided with an outlet (58); the direction of rotation of the saw blade (4) is such that a circumferential part of the blade which has passed beyond the bottom surface of the cover device will move in a direction upwards-rearward towards the bottom surface; and by providing the passage in the covery device, the connection member is connected to the longitudinal passage, when cutting is started and when the cutting depth is shallow, teh dust or slurry can be effectively removed.