The invention discloses a miniaturized TIR prism system for a DLP projector. The prism system comprises a first TIR prism which is adjacent to a DMD chip and a second TIR prism which is attached to the first TIR prism; the second TIR prism includes a CD surface, a DE surface and a CE surface, wherein the CE surface is attached to the first TIR prism, and the DE surface is an outgoing surface. The prism system is characterized in that the prism system further comprises wedge-shaped glass; the wedge-shaped glass is bonded onto the CD surface through an optical adhesive; an angle between the CD surface and the bevel edge of the wedge-shaped glass is Phi, and Phi a positive value; the refraction rate n1 of the second TIR prism is smaller than the refraction rate n2 of the optical adhesive, and the refraction rate n2 of the optical adhesive is smaller than the refraction rate n3 of the wedge-shaped glass. With the miniaturized TIR prism system for the DLP projector of the invention adopted, non-imaging light cannot enter a projection lens, so that imaging quality will not be affected, and the size of the TIR prisms can be reduced.