Abstract: Many plantassociated microbes are pathogens that impair plant growth and reproduction. Plants have evolved a series of complicated defense mechanism against pathogens during their long term process of coevolution. Plants innate immune system efficiently detects and wards off potentially dangerous microbes. A first layer of this system is based on sensitive perception of pathogenor microbeassociated molecular patterns (PAMPs) through pattern recognition receptors (PRRs) at the plants cell surface，which would active mitogenactivated protein kinase(MAPK) signaling cascade and burst early responses in plant resistance to pathogen attacks. The first layer recognizes and responds to many classes of microbes, including nonpathogens. With pathogens produce effectors to inhibit PTI, plants can perceive such effectors through additional receptors, typically nucleotide binding leucinerich repeat (NBLRR) proteins, to mount a second layer of defense called effect or triggered immunity (ETI). Here, we highlight recent literature on plants innate immune system, and based on a detailed understanding of plant immune function, we should focus on the combination of the use of PTI and ETI to expand the antimicrobial spectrum of plant effectively and improve plantss diseaseresistance.