Abstract: OBJECTIVE To establish an LC-PDA method for determination of arecoline, arecaidine, guvacoline and guvacine in Arecae Semen, Arecae Semen Tostum and Arecae Pericarpium. METHODS The sample was soaked with ammonia, and extracted with methanol by ultrasonic extraction. The target compounds were separated on a ZORBAX 300-SCX column(150 mm×4.6 mm, 5 μm) with a gradient elution of acetonitrile(A)-0.2% acetic acid(B) solution(adjusted to pH=3.8 with ammonium) at the flow rate of 0.5 mL·min^-1. The column temperature was 30 ℃, the injection volume was 5 μL, and the detection wavelength was set at 225 nm. RESULTS Arecoline, arecaidine, guvacoline and guvacine showed a good linear relationship with the peak area within 2.98-745.0, 2.60-650.0, 1.19-595.0, 1.22-610.0 μg·mL^-1, respectively(r²>0.999 0). The average recoveries of arecoline, arecaidine, guvacoline and guvacine in Arecae Semen, Arecae Semen Tostum and Arecae Pericarpium were ranged from 95.0% to 105.0%, with RSD<2.50%(n=6). The content of alkaloids in Arecae Semen and its processed products was significantly different. CONCLUSION The proposed method is rapid, sensitive, accurate, reliable, which can be used for the determination of four alkaloids in Arecae Semen, Arecae Semen Tostum and Arecae Pericarpium.