For the method of moments (MOM) based on RWG basis function, a novel method is developed to solve the singular impedance elements efficiently: directly conducting simple variable substitution to surface integrals and transforming them to non-singular integrals, thus reducing the integral complexity and computation. It is simple and efficient to use this method to solve the singular integrals without extracting singularity from singular parts, which eliminates the singularity of the matrix elements effectively and obtains high calculation accuracy. Numerical example shows that the new method, compared to the conventional methods, can greatly improve the computational efficiency and meet the efficient solution of complex targets RCS.