OBJECTIVE： To establish a method for simultaneous determination of gallic acid， protocatechuic acid， catechuic acid， corilagin and brevifolincarboxylic acid in Geranium carolinianum. METHODS： HPLC was performed on the column of WondaSil C18 WR with mobile phase of acetonitrile-0.1％ Phosphoric acid （gradient elution） at a flow rate of 1.0 ml/min， the detection wavelength was 280 nm， the column temperature was 40 ℃， and the volume injection was 20 μl. RESULTS： The linear range was 0.02-20.02 for gallic acid （r＝0.999 9）， 0.01-20.10 for protocatechuic acid （r＝0.999 7），0.02-19.78 for catechuic acid （r＝0.999 6），0.02-20.02 for corilagin（r＝0.999 9） and 0.02-20.10 for brevifolincarboxylic acid （r＝0.999 5）； RSDs of precision， stability and reproducibility tests were lower than ＜3.0％； recoveries were 95.1％-100.6％ （RSD＝2.20％，n＝6）， 95.8％-100.6％ （RSD＝1.74％，n＝6）， 95.1％-101.9％（RSD＝2.71％，n＝6）， 97.7％-103.1％（RSD＝2.04％，n＝6） and 95.3％-99.0％ （RSD＝1.46％，n＝6）. CONCLUSIONS： The method is simple， accurate and reproducible， and can be used for the contents determination of gallic acid， protocatechuic acid， catechuic acid， corilagin and brevifolincarboxylic acid in G. carolinianum.