【Objective】To synthesize a novel Schiff base, 5-(chloromethyl)salicylaldehyde-tyrosine and its maganesium(II) complex with methanol solvent. 【Method】 The ligand and complex were characterized by elemental analysis, molar conductance, IR, UV and TG-DTA. Antibacterial activity, SOD activity of the complex and its interaction with bovine serum albumin (BSA) were examined by filter paper method, photoreduction of nitro-blue tetrazolium (NBT) and fluorescence quenching technique, respectively. 【Result and conclusion】 The ligand and complex formula were K₂L·3H₂O（L=C₁₇H₁₄NO₄Cl^2-） and K［MnL(CH3 ₃COO)］·2H₂O, respectively. The nitrogen atom of imino group and the oxygen atoms of phenol group and carboxyl group in the ligand and one acetate ion were coordinated with the central metal Mn(Ⅱ). The antibacterial experiments in vitro showed that the complex had higher antibacterial activity than the Schiff base. The antibacterial activity against Escherichia coli as a gram-negative bacterium was higher than Staphylococcus aureus as a gram-positive bacterium. The complex had high SOD activity and its IC₅₀ value was 1.616 μmol·L^-1. The complex effectively quenches the intrinsic fluorescence of BSA via static quenching mechanism, and forming a ground-state complex with BSA. The number of binding sites (n) and the binding constant (K_A) at 25 ℃ are about 1 and 1.62×10⁶ L·mol^-1 respectively, and non-radiation energy is transferred red from BSA to the complex possibly.