We optimize the geometric structure and calculate total densities of states, band structures, the relative number of electrons and mobility ratios of electrons of ZnO mode established at different concentrations of Al, in the condition of high concentration of Al heavily doped ZnO semiconductor at low temperature, by adopting the ab-initio study of plane wave ultra-soft pseudo potential technique based on the density function theory (DFT). It is found that the relative number of electrons increases, but the mobility ratio of electrons of ZnO decreases, with the concentration of Al increasing. On the contrary, the lower the Al doping concentration, the stronger the conductivity of ZnOis. The conductivity is compared. We can draw a conclusion that the conductivity of ZnO semiconductor decreases with Al doping concentration increasing. The calculation results are consistent with the change trend of experiments with Al concentrations exceeding o.z, i.e., x≥0.02.