Motivated by recent measurements of the neutral B s-meson mixing,obtained by LHCb group and the Tevatron,and the possibility to have sizable NP effects in Γs12,we revisit the Bs-Bs mixing in a family non-universal Z' model.We assume that the Z ' boson contributes to the off-diagonal elementM s 12 and also to the off-diagonal element Γs12 via tree-level Z'-induced b→scc operators.We find that,with the constraints from △Msφs and the indirect CP asymmetry in Bd→J/ψKs imposed,the present measured 1σ experimenta...