A novel technique for supercritical water gasification, where catalyst is suspended in the feedstock to form slurry in place of putting the catalyst particles in the reactor as a packed bed, has been proposed. To evaluate this process, fundamental characteristics of the slurry is of practical importance. In this study, rheological characteristics of the slurry as a function of solid content, temperature for hydrothermal pretreatment, catalyst loading were determined. Heat transfer characteristics were also measured. Chicken manure was selected as feedstock, and after pulverization and hydrothermal pretreatment, activated carbon catalyst powder was added to form slurry. The apparent viscosity of the product slurry was measured with rotary viscometer, and effects of hydrothermal pretreatment, water content, and amount of added carbon catalyst were determined. It was found that hydrothermal pretreatment followed by pulverization resulted in higher yield of slurry compared to pulverization followed by hydrothermal pretreatment. Addition of activated carbon resulted in linear increase in apparent viscosity, but the pressure drop due to the increase in viscosity did not affect the process efficiency. As for heat transfer characteristics, double tube heat exchanger was employed, and heat transfer coefficient was determined.