Controlling light based on cascading linear electro-optic effect is an effective and widely used method for light modulation. For an one-dimensional photonic crystal like periodically poled lithium niobate (PPLN), while electric field is applied parallel to the optical axis, the refractive index is periodically changed, and an electro-optic photonic crystal is formed. While electric field is applied vertically to the optical axis, not only the size of refractive index ellipsoid is periodically changed, but also the direction of spindle of refractive index ellipsoid is periodically changed. Some of the applications based on cascading electro-optic effect are reviewed, including tunable chirality devices, all optical logic gates, temporal cloak based on simultaneous fast and slow light, and nonlinear optics. The great potential applications of the cascading electro-optic effects in integrated photonic circuit are predicted.