An experimental investigation has been conducted to study fundamental electrohydraulic discharge characteristics and plasma parameters of liquid solution plasmas. HF-bipolar high voltage was supplied to the rod-to-rod type plate electrodes with a few mm gap distance inside water with conductive KCl or Na2SO4 solutions. Experiments are conducted for applied maximum voltage from 1 to 6 kV, the electrode gap distances from 0.3 to 5 mm and for the operating frequency from10 to 15 kHz. Plasma parameters was determined by the optical emission spectroscopy with LTE model and compared with the discharge channel averaged plasma parameter from discharge characteristics. The results show that a stable, liquid solution plasma can be generated by HF PSED. Based on optical emission spectra, a significant hydrogen gas was generated in a spark discharge channel. Morphology of liquid solution plasma and transient plasma density behavior will be discussed in detail.