In this paper, a compact optical high-speed 1-bit comparator is proposed based on photonic crystals. In this structure, the nonlinear rods are used at the cross-connecting point of two optical waveguides. The optical transmission and reflection from these rods depend on the amount of the optical intensity. In response to the different states of the input ports, different values of the optical power reach these rods and the interference patterns make the correct function of the output ports. The refractive index and the Kerr coefficient of nonlinear rods are 1.4m2/W and 10-14m2/W, respectively. The footprint of the structure is 55µm2, which is much smaller than the previous works. Besides, the lower delay time is the other advantage of this work compared with the previous works. Based on the simulation results, the proposed structure can be used in integrated optical circuits.