Optical tweezers have been successfully utilized in various scientific and engineering fields such as optics and microactuators.However,there is still a lack of a sophisticated model for optical tweezers on driving complex microrotors.In this paper,a novel model which is based on the Moment method for optical tweezers to calculate the torque of the complex microrotors is presented.The Poggio-Miller-Chang-Harrington-Wu (PMCHW) formulation is adopted to describe the electromagnetic fields of a microactuator which is controlled by a highly focused laser beam,and it will be transformed into matrix equations.