As a candidate for lead-free piezoelectric materials, dense (NKN-5LT) ceramics were developed by conventional sintering process. Sintering temperature was lowered by adding as a sintering aid. The electrical properties of NKN-5LT ceramics were investigated as a function of concentration. At the addition of 1 mol% , electromechanical coupling factor and piezoelectric coefficient of NKN-5LT ceramics were found to reach the highest values of 0.37 and 250 pC/N, respectively.