The frequency analysis of 64 coupled age differences(Δt=t_Zr-t_Rb)between the zircon U-Pb age(t_Zr) and whole rock RbSr age (t_Rb)for granite plutons shows that theΔt histogram displays a symmetrical normal distribution (skewness C_SK=0.150; kutrocess C_KU=4.274); theΔtare both positive and negative with mode 2.0Ma, but far less than the period of cooling—crystallization (>16 Ma)of a granitic batholith. Using least squares regression procedure, a best regression equation (t_Rb=0.99354t_Zr +2.15163) with high correlation coefficient (r=0.997) is fitted to the 64 points of the zircon UPb age and the whole rock RbSr age for granite plutons. The constant of this regression equation (2.15163Ma) is consistent with theΔt mode (2.0Ma) for the main. These statistical characteristics indicate that the zircon U-Pb dating age is corresponded with the wholerock Rb-Sr isochron age for granite as a whole and the zircon U-Pb dating age cannot represents the emplacement age of a granite batholith.