Li1.3Al0.3Ti1.7(PO4)3 pellets sintered with different mole percentage of Li3PO4 were prepared by sol-gel method. The structural identification, surface morphology, electrochemical window, ionic conductivity and activation energy of the sintered pellets were studied by X-ray diffraction, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The results show that all the Li1.3Al0.3Ti1.7(PO4)3 pellets sintered with different mole percentage of Li3PO4 have similar X-ray diffraction patterns. The Li1.3Al0.3Ti1.7(PO4)3 pellet sintered with Li3PO4 has lower porosity and is denser than the pellet without Li3PO4. The addition of Li3PO4 has relatively large effect on the porosity and density of the sintered pellet, however has little effect on the electrochemical window of Li1.3Al0.3Ti1.7(PO4)3. Among the Li1.3Al0.3Ti1.7(PO3)4 pellets sintered with different mole percentage of Li3PO4, the one sintered with 1% Li3PO4 shows the activation energy of 0.3142 eV and the highest ionic conductivity of 6.15?10-4 S.cm-1.