Na2O excess 95(Na0.5K0.5)NbO3-5LiTaO3 (NKN-5LT) ceramics were developed by conventional sintering process. Sintering temperature was lowered by adding Na2O as a sintering aid. Grain growth behaviors with Na2O addition were explained in terms of the effect of Na2O on interface reaction - controlled grain growth and the critical driving force. The electrical properties of NKN-5LT ceramics were investigated as a function of Na2O concentration. In the 1 mol% Na2O excess NKN-5LT samples sintered at 1000oC for 4h in air, electromechanical coupling factor (kP) and piezoelectric coefficient (d33) of NKN-5LT ceramics were found to reach the highest values of 0.43 and 190 pC/N, respectively.