An experimental investigation has been conducted to study a fundamental electrohydraulic discharge characteristics and plasma parameters in a dielectric liquid solution with Ar gas injections. HF-bipolar high voltage was supplied to the converging angle type plate electrodes with 1mm gap distance inside dodecane with conductive salt solutions. Experiments are conducted for Ar gas flow rate from 0.1 to 1 L/min., applied maximum voltage from 10 to 60 kV for the operating frequency fromlO to 15 kHz. The results show that HF PSED can be generated relatively stable discharge even in the dielectric fluid and gold nano-particles were fabricated. Morphology of liquid solution plasma and transient plasma density behavior will be discussed in detail.