A mill roller transmission mechanism comprising a frame, a fast roller, a slow roller and a toothed belt; wherein the toothed belt is provided with an inner toothed surface and an outer toothed surface, the inner toothed surface of the toothed belt is engaged with a peripheral surface of the fast roller, the outer toothed surface of the toothed belt is engaged with a peripheral surface of the slow roller; wherein the mill roller transmission mechanism further comprises: a tensioning seat fixed to the frame; a support shaft, with one end pivot-jointed to the tensioning seat; a swing frame, with one side fixed to the support shaft and driving the support shaft to rotate; a rolling shaft, pivot-jointed to the other side of the swing frame, with its axial direction parallel to the axial direction of the support shaft; a tensioning wheel, with its central axle hole fitted over and fixed to the rolling shaft and its peripheral surface engaged with the inner toothed surface of the toothed belt a press mechanism connected between the swing frame and the tensioning seat in an elastically adjustable manner and designed to adjust the deflection angle of the swing frame; wherein the press mechanism comprises: a tension rod, with one end connected to the tensioning seat and the other end provided with threads, wherein the tension rod is pivot-jointed to the tensioning seat via a connecting shaft; a spring fitted over the rod of the tension rod with its top end biased on the swing frame; an adjusting nut fitted over the end of the tension rod provided with threads and abutting the bottom of the spring; wherein a first gasket is provided between the top end of the spring and the swing frame, and a second gasket is provided between the spring and the adjusting nut; wherein the first gasket has a positioning pivot point located on the jointing part with the swing frame, and the swing frame has a recessed part corresponding to the positioning pivot point. a tensioning seat fixed to the frame; a support shaft, with one end pivot-jointed to the tensioning seat; a swing frame, with one side fixed to the support shaft and driving the support shaft to rotate; a rolling shaft, pivot-jointed to the other side of the swing frame, with its axial direction parallel to the axial direction of the support shaft; a tensioning wheel, with its central axle hole fitted over and fixed to the rolling shaft and its peripheral surface engaged with the inner toothed surface of the toothed belt a press mechanism connected between the swing frame and the tensioning seat in an elastically adjustable manner and designed to adjust the deflection angle of the swing frame; a tension rod, with one end connected to the tensioning seat and the other end provided with threads, wherein the tension rod is pivot-jointed to the tensioning seat via a connecting shaft; a spring fitted over the rod of the tension rod with its top end biased on the swing frame; an adjusting nut fitted over the end of the tension rod provided with threads and abutting the bottom of the spring; wherein a first gasket is provided between the top end of the spring and the swing frame, and a second gasket is provided between the spring and the adjusting nut; wherein the first gasket has a positioning pivot point located on the jointing part with the swing frame, and the swing frame has a recessed part corresponding to the positioning pivot point.