We demonstrate the nanofabrication of the transmission SU-8 gratings with periods from 200 nm (5000 lines/mm) to 1 lm (1000 lines/mm) with different trench depths for applications from near-infrared to deep-UV wavelength. The imprint property of SU-8 under various pressures and temperatures was systematically studied and agreed well with the simulation results. The effects of trench depth on diffraction intensity profiles were simulated and results show periodic diffraction orders with varying intensity distributions, which is in good accordance with the results from optical measurements. The high optical transmittance of SU-8 in the visible range and its low volume shrinkage coefficient make the developed process an ideal candidate for high-volume manufacturing of various gratings at low cost.