Abstract:After pathogen infection, plant will acquire a long lasting broad-spectrum resistance, known as systemic acquired resistance (SAR).Plant can also acquire a similar SAR after insect attack.The signal molecules of these two kinds of SAR are different: Of pathogen, it is salicylic acid (SA);And of insect, it is jasmonic acid (JA), methyl-jasmonic acid (Me-JA) or systemin. SAR signal transduction pathways mediated by JA, Me-JA or systermin is not thoroughly independent of by SA, but has a cross-talk between them, and whether the influence of their cross-talk on each other is promotion or reduction is still unknown. But it is undoubted that research on this subject will contribute to the foundation of plant protection strategies.