In this paper,peanut kernels were firstly roasted at 180 ℃ for 20 min,then grounded and defatted or further hydrolyzed with alcalase to compare the solubility,in vitro digestibility,emulsifying properties and antioxidant properties of peanut protein. Results showed that roasted treatment reduced solubility,emulsifying activity,while increased digestibility,emulsifying stability,hydroxyl radical-scavenging ability,and Fe2 +-chelating ability. Enzymatic hydrolysis with alcalase significantly( P < 0. 05) improved the solubility,emulsifying stability,hydroxyl radical-scavenging activity and Fe2 +-chelating ability. Furthermore,hydrolysates from raw and roasted peanut flour hydrolyzed respectively for 8 h and 6 h were characterised by the highest hydroxyl radical-scavenging activity. Thus,these results revealed that roasting treatment and enzymatic hydrolysis affected functional properties and antioxidant activity of peanut protein,and put in evidence for developing the defatted peanut meal,a low value by-product of peanut oil production.