Abstract: The steep and intense pressure waves generated by the arc in oil is the direct cause of transformer tank explosions and subsequent fires. Understanding the generation and propagation characteristics of these pressure waves in transformer oil is crucial for improving disaster prevention measures. This study employs a pulsed arc discharge method in oil to generate pressure waves, significantly reducing the interference from continuous gas production and reignition observed in power frequency arc experiments. An integrated optical-electrical diagnostic platform was constructed to collect signals of voltage, current, and pressure time series and dynamic schlieren images, so as to analyze the pressure wave generation in oil. The experimental results reveal that the generation of pressure waves in oil can be divided into two stages: arc expansion and bubble pulsation. In the microsecond time scale, the arc channel rapidly expands and compresses the oil medium, generating a series of shock waves that superimpose to form a high-frequency primary pressure wave. During the discharge process, the generated bubbles undergo multiple cycles of expansion and collapse, forming secondary pressure waves upon collapse, characterized by higher pressure and lower frequency. Increasing the electrode spacing transforms the primary pressure wave from a spherical wave to a cylindrical wave along the electrode direction. Furthermore, the non-uniform pressure distribution and the influence of the electrode structure lead to significant wavefront thickness due to the superposition of secondary pressure waves generated at multiple points. Experimental data fitting indicates that the attenuation coefficient of pressure waves in oil is approximately 1.2~1.4, significantly higher than the attenuation coefficient in water. This suggests a faster attenuation rate of pressure waves in oil due to viscous loss, thermal conduction, and energy dispersion.