Infrared detection has been widely used in military area. How to reduce the probability of military targets from being detected and discovered by infrared detector has become an urgent problem. As a new kind of artificial structure material，photonic crystals have wide applications in the infrared stealth field because of its high reflectivity of the photonic band gap and low radiation characteristics. The basic concept and characteristics of photonic crystals are presented and the research status of photonic crystals are reviewed.