A new phenylethanoid glycoside, named taraffinisoside A (1), together with five known glycosides were isolated from the stems and leaves of Tarphochlamys affinis. The structure of taraffinisoside A was identified on the basis of detailed spectral analysis. Compounds 1-4 and 6 showed potent antioxidant activities with $IC_{50}$ values of 10.36, 19.73, 43.95, 15.30 and $46.04{mu}M$ by 1,1-diphenyl-2-picryhydrazyl radical-scavenging assay. Compounds 1, 2 and 4 showed anti-HBV activities, with $IC_{50}$ values of 0.50, 0.72 and 0.26 mM for HBsAg and 0.93, 0.42 and 0.07 mM for HBeAg, respectively.