Based on the density functional theory (DFT), using first-principles plane-wave ultrasoft pseudopotential method, the models for the unit cell of pure ZnO and Zn1-xTMxO (TM=Al, Ga, In) supercells at the same doping concentration were constructed, and the geometry optimization, total density of states, band structures for all models were carried out. The calculation results show that, In-doped ZnO has the best conductivity at the same doping concentration of 3.125 at% of (Al, Ga, In) high doped in ZnO, the calculation results agree with the experimental results.