OBJECTIVE To determine 4 kinds of triterpenoid acids in Ganodermna lucidum, namely ganoderic acid C2, ganoderenic acid A, ganoderic acid A and ganoderic acid D quantitively. METHOD The RP-HPLC method was applied and the separation was performed on a Kromasil C18 analytical column (4.6 mm x 250 mm, 5 microm). The mobile phase was acetonitrile (A)-water containing 0.03% H3PO4 (B) with gradient elution mode at the flow rate of 1.0 mL x min(-1). The detection was set at 252 nm, and the column temperature was 35 degrees C. RESULT The linear ranges of ganoderic acid C2, ganoderenic acid A, ganoderic acid A and ganoderic acid D were 5.0-50.0 microg x mL(-1) (r = 0.9999), 7.2-72 mg x L(-1) (r = 0.9998), 11.67-116.7 mg x L(-1) (r = 0.9999), 5.32-53.2 mg x L(-1) (r = 0.9996), respectively. The average recoveries (n=9) were 98.8% (RSD 1.5%), 99.1% (RSD 1.9%), 99.5% (RSD 1.4%), 98.5% (RSD 1.9%), respectively. CONCLUSION The method is simple and accurate with a good reproducibility and can be used as a quality control method for G. lucidum of different sources.