Transversal SAW(Surface Acoustic Wave) filters of 340MHz were fabricated on piezoelectric substrates of the LN $128^{circ}$ Y-X wafers. Both of spacing and width of IDT were $1.435{mu}m$. For improving the power durability characteristics, titanium layer was inserted between aluminum electrode and piezoelectric substrate since it has high density, low thermal expansion coefficient, and good adhesive properties. Power durability was evaluated with respect to the thickness of inserted titanium layer and the temperature of heat treatment. Power durability is improved with increasing the thickness of the inserted titanium layer. Moreover, it is remarkably improved by heat treatment at the temperature of $300^{circ}C$.