The invention discloses a novel crystal form of oxalate of dipeptidyl peptidase inhibitor, namely, (s)-1-(2-(2-(3-(3,4-dimethoxyphenyl)-2-oxo-1-imidazolidinyl)ethylamino)acetyl)-2-cyanpyrrolidine oxalate. In X-ray powder diffraction of the crystal form, characteristic peaks occur at 2 theta diffraction angles of 4.5+/-0.1, 5.5+/-0.1, 9.0+/-0.1, 10.9+/-0.1, 16.4+/-0.1, 17.7+/-0.1, 18.1+/-0.1, 22.0+/-0.1, 22.7+/-0.1, 25.6+/-0.1, 28.1+/-0.1, 28.4+/-0.1 and 32.0+/-0.1. The crystal form disclosed by the invention is superior to the original oxalate in stability, and is more stable for light, heat and humidity and convenient to store and transport; the cost of the DPP-IV (dipeptidyl peptidase-IV) inhibitor in transportation and preservation processes is decreased; and the safety of the product is further guaranteed.