The in-plane resistivity ρab(T) and the out-of-plane ρc(T) have been extensively measured for pure single crystal Bi2Sr2CaCu2O8+δ(Bi2212) annealed at different oxygen pressures.The ρc(T) and anisotropy (ρc(T)/ρab(T)) decrease rapidly with increasing carrier concentration.It is found that the out-of-plane resistivity decreases linearly with decreasing temperature down to about 120K for the overdoped sample,its resistivity anisotropy is of weak temperature dependence.The data of ρc(T) and ρc(T)/ρab(T) are well fitted by the bipolaron theory proposed by Alexandrov and Mott.