The rotor profiles are the key factor of twin-screw compressor,but there is some inconvenience in modification and experiment of rotor profile. NURBS curves and computational fluid simulation analysis are applied to overcome these two problems. NURBS curves are introduced to construct a new rotor profile based on the rotor profile of unilateral asymmetric combined cycloid with pin gear arc. The equations of profile are given. The numerical simulation models of the new profile and the original profile are built to find out the distribution law of pressure and velocity in twin-screw compressors under the operating speed by the means of FLUENT software. Finally,according to the simulation results,the rationality of the designed rotor profile is verified,and new schemes for further optimization are explored. Then an experiment is made to describe the reliability and convenience of this design method.