A lampshade module capable of replacing optical projection elements for combining on a lamp to adjust the light projection angle of light-emitting diodes of a light-emitting module, the lampshade module comprising: a lens holder comprising a front surface, an opposing bottom surface, a plurality of lens holes recessed from said front surface toward said bottom surface and at least one first buckle portion located on a hole wall of each said lens hole, each said lens hole having a back end corresponding to one respective said light-emitting diode of said lamp; and a plurality of lenses respectively inserted into said lens holes of said lens holder, each said lens being a light-transmitting lens, each said lens comprising a light entrance surface, a light-emitting surface opposite to said light entrance surface and at least one second buckle portion formed around the periphery thereof, the at least one second buckle portion being for buckling and fixing on said at least one first buckle portion of the respective said lens hole to hold down each lens in the respective said lens hole, wherein the aforementioned lens holder further comprises a plurality of bumps protruding from the bottom surface thereof corresponding to the lens holes, so that the lens holes are respectively recessed into the bumps, characterized in that said light entrance surface being a convex arc surface protruding in direction toward one respective said light-emitting diode, said convex arc surface being used to cause the light of the respective said light-emitting diode to enter and project at a light projection angle, wherein each said lens further comprises a back end opposite to said light-emitting surface and a groove recessed from said back end in direction toward said light-emitting surface, and the associated said light entrance surface is formed at a bottom of said groove, wherein the arcs of said convex arc surfaces of said lenses are different and adapted for projecting light at different light projection angles. a lens holder comprising a front surface, an opposing bottom surface, a plurality of lens holes recessed from said front surface toward said bottom surface and at least one first buckle portion located on a hole wall of each said lens hole, each said lens hole having a back end corresponding to one respective said light-emitting diode of said lamp; and a plurality of lenses respectively inserted into said lens holes of said lens holder, each said lens being a light-transmitting lens, each said lens comprising a light entrance surface, a light-emitting surface opposite to said light entrance surface and at least one second buckle portion formed around the periphery thereof, the at least one second buckle portion being for buckling and fixing on said at least one first buckle portion of the respective said lens hole to hold down each lens in the respective said lens hole, wherein the aforementioned lens holder further comprises a plurality of bumps protruding from the bottom surface thereof corresponding to the lens holes, so that the lens holes are respectively recessed into the bumps, characterized in that said light entrance surface being a convex arc surface protruding in direction toward one respective said light-emitting diode, said convex arc surface being used to cause the light of the respective said light-emitting diode to enter and project at a light projection angle, wherein each said lens further comprises a back end opposite to said light-emitting surface and a groove recessed from said back end in direction toward said light-emitting surface, and the associated said light entrance surface is formed at a bottom of said groove, wherein the arcs of said convex arc surfaces of said lenses are different and adapted for projecting light at different light projection angles.