Lead free (1-x)Bi0.5Na0.5TiO3-xKNbO3 piezoelectric ceramics where x = 0.00, 0.05, 0.10 and 0.15 were fabricated by two step sintering method. The effect of KNbO3 on structure, physical, dielectric, ferroelectric, piezoelectric properties was systematically investigated in order to search the lead-free piezoelectric materials with an excellent performance. It was found that, the dielectric constant was increased with increasing KNbO3 content. This At room temperature, piezoelectric coefficient of 84.97 pm/V and low Ec4.25 kV/cm with highest Pr1.407 C/cm2 were obtained for the composition of x=0.05.