The color-octet mechanism for the decay B-->eta'X is proposed to expla
in the large branching ratio of B(B-->eta'X)similar to 1x10(-3) recent
ly announced by CLEO. We argue that the inclusive eta' production in B
decays may dominantly come from the Cabibbo-favored b-->(<(cc)over ba
r>)(8)s process where the <(cc)over bar> pair is in a color-octet conf
iguration, and followed by the nonperturbative transition (<(cc)over b
ar>)(8)-->eta'X. The color-octet intrinsic charm component in the high
er Fock states of eta' is crucial and is induced by the strong couplin
g of eta' to gluons via the QCD axial anomaly.