All-optical logic devices play a very important role in the fields of alloptical computing system, ultrahigh speed information processing, and optical communication. Adopting photons instead of electrons as the information carriers can achieve higher data transmission rate, lower energy losses, and really parallel processing ability. The central processing unit (CPU) is the arithmetic core and the controlling core of an electronic computer. The central processing unit consists of a large number of electronic logic devices, such as various logic gates, adder, multiplier, divider, and so on. The photon is adopted as the information carrier in the all-optical computing system. Therefore, it is necessary to achieve all-optical logic devices. The realization of all-optical logic devices mainly depends on the interactions of photon and matter. The photonic crystal possesses unique properties of controlling the propagation states of photons due to the photonic bandgap effect. Moreover, two-dimensional semiconductor photonic crystal can be easily integrated into the photonic integrated circuits. Great efforts have been made to realize photonic crystal all-optical logic devices. However, up to now, there has been little progress in the research of photonic crystal logic devices.