A simple approach based on polarization to process binary all-optical logic signal with validation is proposed, by electro-optic Pokels effect. In experiment, we choose optical signal with two orthogonal linear polarization states to present logic 1 and 0. This approach can alter the polarization state of input optical signal about 90°on the polarization plane based on electro-optic modulation of periodically poled lithium niobate (PPLN). Optical signal can be switched between the two orthogonal polarization states, and polarization direction will be not changed without external applied electric field. Therefore, it can realize controllable-NOT function. If we choose external applied electric field to present logic 1 and 0, it can realize NOR and XNOR functions. In this approach, digital logic signal is carried on the polarization state of optical signal. The dissipation of intensity of optical signal is very small in this process, so this approach is more advantageous for multiply cascaded systems ,comparing with traditional approach ,in which digital logic signal is carried on the intensity of optical signal.