An electro-optic deflector based on negative refraction effect of a two-dimensional Photonic Crystal (PC) infiltrated with liquid crystal was proposed. The deflector was achieved by applying the electric field which could rotate the angle of liquid crystal molecules. By using the Plane Wave Expansion method and 2D-finite-difference time-domain (2D-FDTD) method on software RSoft CAD, negative refraction effect and the self-collimation effect of photonic crystal were demonstrated. The separation of light path and deflection could be realized by the negative refraction effect, and simulation data were analyzed. The result shows that the deflection range can be achieved up to 20° and the deflection angle linearly varies with the refractive indices.