Abstract: In order to compare the oleoresin from green, black and white pepper, the extraction conditions were optimized by the L9 (34) orthogonal experiment with the raw materials.Soaking and ultrasonic time, solute volume was optimized for processing oleoresin.The components of oleoresin were then determined by GC-MS method.The results showed that 25 components were isolated from oleoresin in green pepper, of which 20 were identified;28 components were isolated from oleoresin in black and white pepper, of which 23 were identified, respectively.The main aroma components of oleoresin were α-pinene, β-pinene, 3-carene, D-limonene, 4-ethenyl-4-methyl-3- (1-methylethenyl) -cyclohexene, caryophyllene, piperine and so on.As the extraction ratio of oleoresin was the highest, the aroma was fresher and the relative amount of compounds was slightly lower than that of black and white pepper, oleoresin of green pepper could be an ideal material to develop new kinds of products instead of that of black and white pepper.