Quasi-phase matched sum-frequency generation (SFG) and electro-optic (EO) polarization coupling has been realized simultaneously in a periodically poled lithium niobate on insulator (PPLNOI) ridge waveguide. Therefore, utilizing the cascading process, the intensity of sum-frequency conversion can be modulated by applying a transverse electric field. The driving voltage is reduced by using the ridge waveguide structure, and also the frequency conversion efficiency is enhanced. This scheme is proposed to control nonlinear frequency conversion by electric field applying on the lithium niobate on insulator (LNOI) platform. The integration and fast-speed modulation of the configuration may find applications in nonlinear optical processing and communication.