Taking Lizao as tries the material,this experiment studies 0.01,0.1 and 1 mmol/L three different density MeJA processes after picks Lizao disease resistance influence. The findings indicate that,in this experiment the 0.01 mmol/L processing enhances the activities of phenylalanine ammonia lyase(PAL),polyphenlo oxidase(PPO),peroxidese(POD) and total phenols,and strengthens Lizao disease.