Two phenolic compounds, ginnalin B and ginnalin C, have been solated and characterized.from the leaves of Acer ginnala Maxim, both of them have been shown to possess antibacterial activities, in vitro, towards Shigella flexneri, Shigella sonmei and so on.Ginnalin B, C₁₃H₁₆O₉, m.p.133-134℃,[a]_D¹⁹+14.8° (c, 2.5, acetone), UV (MeOH):217 (4.36), 277(3.94) nm, (MeOH+NaOH):278, 320 nm is soluble in methanol, ethanol, acetone and water.It reacts with FeCl³ to give a blue colony.Ginnalin C is colorless crystals with formula C₁₃H₁₆O₉, m.p.251-252℃,[a]_D²⁰+64.80 (c, 2.7, DMSO), it is soluble in dimethyl sulfoxide, methanol and ethanol, UV (MeOH):218 (4.43),277 (4.00) nm.Their structures were established by means of chemical and spectral analyses as polygalitol 6-gallate and 2-gallate respectively.Other seven compounds have been isolated, and sig of them identified as gallic acid, ethyl gallate, qnebrachitol, ellagic acid, qnercetin and,B-sitosterol, the structure of compound 10 is to be determined.