This paper describes the design and development of a high-power high-resolution pulser designed especially for air-coupled ultrasonic nondestructive evaluation applications requiring high material penetration capability. The pulser can deliver up to 800 V in a spike excitation type pulse to appropriate low/medium frequency transducers. Moreover, the pulser operates in three different modes: single pulse, double pulse (pulse cancellation technique), and external reference signal, where the last two operating modes are intended to enhance the axial resolution of ultrasonic inspections. Experimental results show that the received pulse duration can be significantly reduced, and reduction factors of 2 or 3 in the pulse duration can be easily achieved.