The invention discloses a winding device of a straw weaving machine. The device comprises a mounting frame as well as a winding mechanism and a shearing mechanism which are arranged on the mounting frame; the shearing mechanism comprises a cutting mechanism and a guiding component for guiding the front surface and the back surface of a woven mat below cutting heads of the cutting mechanism; the cutting mechanism comprises the two cutting heads, a cutting driving mechanism and a stroke driving mechanism; each cutting head comprises a cutting cover and a cutter arranged inside the cutting cover;the mounting frame comprises a first bearing plate and a second bearing plate which are located above and below the guiding component separately; the two cutting heads are located above the first bearing plate and the second bearing plate separately; and during working, the upper surface of the first bearing plate and the upper surface of the second bearing plate directly face the front surface and the back surface of the woven mat separately. By the aid of the winding device, burrs of the woven mat can be removed during winding, tilted straw tails swinging freely can be removed, and thus thesurface quality of the woven mat can be effectively improved.