To decipher the role of jasmonate in chemical elicitor L-glutamate induced resistance to pathogens， tomatoes were treated with 0.1 mg/mL L-glutamate and/or 0.1 mmol/L methyl jasmonate. After inoculating with Alternaria alternata spore suspension， disease incidence of fruit was observed. The effect of L-glutamate on jasmonate biosynthesis and signaling pathways were analyzed by reverse transcription quantitative real-time polymerase chain reaction at the transcriptional level. The results showed that the disease incidence decreased by 35% in L-glutamate treatment compared with the control， while there was no significant difference between L-glutamate and the control in methyl jasmonate group. Concurrently， allene oxide synthase， allene oxide cyclase， coronatine insensitive 1， transcription factor MYC2 and protease inhibitor PI-II were down-regulated by L-glutamate， accompanied by higher expression level of the negative regulator JAZ1. Collectively， the inhibition of JA pathway might be involved in L-glutamate induced resistance to Alternaria alternata in tomato fruit. These findings provided a better understanding for L-glutamate mediated resistance， leading to more sufficient theoretical basis for its commercial application.