The invention discloses a seam beautifying and grooving device. The seam beautifying and grooving device comprises a handle, wherein a separable fixing sleeve is arranged on the head of the handle; a connecting thread is arranged on the outer wall of the tail end of the handle; the fixing sleeve comprises a cylindrical sleeve body; a sleeve inner thread is arranged on the inner wall of the sleeve main body; a pair of parallel fixing side plates is arranged on the outer wall of the sleeve main body; a perforative adjusting arc groove and a rotating round hole are respectively formed in each fixing side plate; guiding oblique planes which are inclined are respectively arranged at two ends of each fixing side plate; and a turnover elongated grooving knife bar is arranged between the fixing side plates. The seam beautifying and grooving device is compact in structure and convenient to adjust; the grooving depths are consistent; and therefore, the seam beautifying and grooving device is particularly suitable for earlier-stage operation of seam beautifying of modern rooms.