The discharge performance of the water-stable lithium electrode (WSLE) is improved by introducing the surface modification of the glass-ceramic plate (LAGP and LATP). The water-stable lithium electrodes are prepared with the NASICON-type glass-ceramic plates as protection layer, and using organic electrolyte as interlayer. The glass-ceramic plates with ionic conductivity of 4 × 10−4−5.7 × 10−4 S cm−1 are water-stable and 300–500 μm thick. The modified layer is deposited onto the glass-ceramic plates by RF magnetron sputtering from a Li4Ti5O12 target. The modified layer is analyzed by XRD, SEM-EDX, Raman and XPS. The Li-air test-cells are assembled with an SCE as reference electrode in aqueous solution. In the Li-air test-cells, the AC impedance and constant polarization potential measurements are carried out to identify the improvement of modification. The impedance of interface between the glass-ceramic plate and organic electrolyte decreases about 20–50%. Consequently, the discharge current is promoted about 70–80%. Then, by introducing interfacial modification of glass-ceramic plate, the power performance of WSLE is remarkably promoted.