Abstract: Monte-Carlo simulation program NGT2002 is used to study the transmission efficiency of curved neutron guide from character wavelength, film reflectivity, film (material,) geometry adjustment error, gap between guides and guide fabricate error, we get the transmission efficiency curves of the Ni, supper mirror curved neutron guides, also we have a discuss of how to choose the curved neutron guide's character wavelength. By the simulation results, we determine the proper film reflectivity value, guide horizontal geometry adjustment error range, optimized gap value between guide elements and guide width fabricate geometry error range.