Disclosed herein is a heating system of floating floor structure including a heating panel with a circular or elliptical inner fluid pathway. The heating panel having the circular or elliptical inner fluid pathway overcomes limitation on pressure resistance, which is the problem of the convention heating panel having a hexagonal fluid pathway, thereby providing enhanced pressure resistance. Furthermore, a floating floor structure of the heating system enhances thermal efficiency, and effectively improves sound absorbing/dampening function in a floor of a building. Additionally, the floating floor structure is provided with inner spaces, which allow utility equipment, such as an electric wire or a pipe, to be easily established therein, thereby enabling an easy repair of the heating system and the utility equipment.