Antioxidant and antibacterial activities in vitro of three major components dl-limonene, γ-terpinene and α-terpineol contained in Eureka lemon peel essential oil as well as its compound were explored in mainly in the determination of DPPH free radical as well as OH· free radical scavenging ability and its bacteriostasis size and MIC against Escherichia coli, Bacillus subtilis and Staphylococcus aureus of the three major components. Results showed that dl-limonene, γ-terpinene, α-terpineol had certain scavenging effect on OH· free radical with clearance rate between 48.45%～77.94%; and the scavenging effect of DPPH free radical was higher than that of LEO at the same concentration. Antibacterial activity test results indicated that dl-limonene, γ-terpinene, α-terpineol showed certain inhibitory effects against the three tested bacteria and lower than that of LEO at the same concentration, α-terpineol showed a best antibacterial effect on Escherichia coli and Bacillus subtilis with MIC 3.9 μL/mL and 1.0 μL/mL respectively, while dl-limonene had better antibacterial effect on Staphylococcus aureus with MIC 1.0 μL/mL; compound composed of dl-limonene, γ-terpinene, α-terpineol showed better antimicrobial effect than monomers. Overall experiment results showed that dl-limonene, γ-terpinene and α-terpineol had certain influence on LEO’s antioxidant and antibacterial activity.