The type Ⅲ secretion system (T3SS) effector is considered as one of the key virulence factors in Xanthomonas oryzae. X. oryzae pv. oryzae and X. oryzae pv. oryzicola cause bacterial leaf blight and bacterial leaf streak in rice, which are important bacterial diseases of rice. Based on bioinformatic analysis of the bacterial genome and other recent reports, X. oryzae contains at least 28 classes of T3SS effectors, divided into two groups: TAL (transcription activator-like) effectors and non-TAL (non tran-scription activator-like) effectors. This paper reviews the number, classes, structure and host targets of T3SS effectors in X. oryzae, which may provide a new insight into the mechanism of rice-X. oryzae in-teraction, regulatory network and molecular breeding of rice.