Abstract: The article mainly studied two enzymes related to Salicylic acid（SA） signaling pathway：phenylalanine ammonia-lyase（PAL）and β-1，3-glucanase（β-1，3-GA）in marine algae Gracilariopsis lemaneiformis，and measured their activity change under sick，high salt，high temperature stresses and addition of SA. Results showed that the activities of PAL and β-1，3-GA in G. lemaneiformis of 3 sick groups increased 1.27-1.42 times and 1.26-1.35 times compared to healthy groups，respectively. For high salt stress，the activities of PAL had no significant difference from the control，whereas β-1，3-GA increased 1.90 times and 1.42 times at 24 h and 48 h compared to the control，respectively. The activities of PAL and β-1，3-GA under high temperature stress increased 1.25 times and 1.27 times compared to the control groups. The activities of PAL and β-1，3-GA increased after adding 100 μmol/L SA，but high concentration of SA inhibited the activities of 2 enzymes. This study indicated that the increases of activities of PAL and β-1，3-GA in G. lemaneiformis might be associated with the SA resistance to environment. In addition，100 μmol/L SA had the most significant effect on the induction of PAL and β-1，3-GA activities.

Key words: Gracilariopsis lemaneiformis, salicylic acid, phenylalanine ammonia-lyase, β-1, 3-glucanase