Abstract: To utilize resveratrol resource in peanut roots,membrane separation had been employed in the preliminary separation of resveratrol in crude extract of peanut roots.Process parameters and influencing factors of a sequential membrane separation system consisting of ultrafiltration and nanofiltration were investigated through comprehensively considering performances of permeate flux,permeability,rejections of resveratrol and soluble sugar. Results showed that ultrafiltration membrane UE030 and nanofiltration membrane NF4 were suitable to separate resveratrol from crude extract of peanut root.p H of extract of peanut root had a significant influence to the performance of nanofiltration membrane on rejection of resveratrol. Operational pressure would remarkably affect permeate flux and permeability of nanofiltration membrane,but insignificantly affect rejections of resveratrol and soluble sugar.The optimal process of membrane separation was as follows: crude extract of peanut root was firstly ultrafiltrated by UE030 under 1 MPa,400 r / min,then the permeate of ultrafiltration was nanofiltrated by NF4 under3 MPa,400 r / min,finally the concentration of soluble sugar decreased from( 1.1832 ± 0.0718) mg / m L to( 0.0475 ±0.0007) mg / m L,the concentration and recovery of resveratrol were( 4.4730 ± 0.0129) ug / m L and( 55.84% ±0.16%),respectively. It could be concluded that membrane separation manages to preliminarily separate and purify resveratrol from peanut roots,which promoted the development of commercial production of resveratrol from peanut roots.