Chitinases belong to family 18 glycosyl hydrolases that can hydrolyze chitin by cleaving β-1,4-glycosidic bond, and are at key points in the life cycles of organism. The inhibitors of chitinases not only have chemotherapeutic potential against fungi, insects, but also hold anti-inflammatory efficacy against asthma and allergic disease in human. This review summarizes the structural characters of chitinases, the proposed catalytic mechanism, furthermore, also gives descriptions of currently existing inhibitors. In addition, computational studies of the interaction modes of chitinases with different inhibitors and substrates, as well as the inhibitor design of chitinases, are summarized so as to obtain an overall understanding for chitinases.