High-frequency pulsed arc welding is an effective technique for optimizing the microstructure andproperties of weld joints. Currently most researches focus on arc-induced ultrasonic effect under ultrasonic pulses. To determine the effect of high-frequency pulsed arc at non-ultrasonic frequency on the nickel-based alloy weld microstructure, high-frequency pulsed tungsten inert gas (TIG) welding which is of low-ultrasonic frequency was employed to investigate welding characteristics of Inconel 690 (Ni–Cr–Fe) alloy. The characteristics and microstructure features of regular TIG welding and high-frequency pulsed TIG arc welding were systematically compared and analyzed. The results demonstrate that a pronounced arc compression effect occurs under high-frequency pulsed arc conditions, accompanied by a significant increase in arc pressure. The primary dendrite growth is inhibited, resulting in homogeneous growth orientation of dendrite, while the secondary dendrite spacing exhibits minor variation (approximately 3.6 μm). Moreover, the element distribution among dendrites of weld region is notably homogenized, with a significant reduction in Cr-depleted area. This study provides theoretical insights into optimizing welding quality of nickel-based alloys using non-ultrasonic frequency highfrequency pulsed welding.