Abstract: Paeonol was isolated from the root of Paeonia Suffruicosa. A derivative of paeonol, 3-hydroxy-1-(2-hydroxy-4-methoxyphenyl)-3-(2'-bromophenyl)-1-acetone, was synthesized by nucleophilic addition of paeonol with 2-bromobenzaldehyde at room temperature in a yield of 78.6%. The structure of this compound was identified by UV, IR, MS, NMR and elemental analyses and was confirmed by X-ray analysis. It belongs to monoclinic crystallographic system with space group P2(1)/n and a=0.993 80(15) nm, b=0.806 17(12) nm, c=1.925 1(3) nm, α=90.0(2)°, β=103.287(2)°, γ=90(2)°, V=1.501 0(4) nm3, Dc=1.554 mg/m3, μ=2.751 mm-1, F(000)=712, Z=4, R1=0.029 0, ωR2=0.066 0, R(int)=0.032 2. The minimum inhibitory concentration (MIC) of this compound against plant pathogenic fungi of Sclerotinia sclerotiorum and Botrytis cinerea were 0.36 and 0.48 g/L, and MIC value against Shigella flexneri 51065 and Staphylococcus aureus ATCC25925 were 0.02 and 0.06 g/L, respectively.