The utility model relates to a plastic refractory system window, including the window frame, the casement, well club, fire prevention glass, casement and window frame, well club constitutes the window that can open, the casement includes window sash frame and casement fire prevention glass, window sash frame includes the section bar and sets up the lined steel in the section bar, set up fire prevention sealing strip A between casement fire prevention glass's outdoor side and the section bar, set up fire prevention sealing strip B between casement fire prevention glass's indoor side and the section bar, be equipped with fire prevention inflation strip in the section bar cavity between casement fire prevention glass and the lined steel, cavity interior division between window frame and the window sash frame is set up defences fiery sealing strip B and is sealed with fire prevention sealing strip C, fire prevention inflation strip is including fire -retardant inflation inner core and the fire -retardant coating of coating on fire -retardant inflation inner core. The utility model discloses a fire prevention can reach more than 0.5 hour in the time limit, and is the plastics window, has good fire behavior and thermal insulation performance, can reduce cost, improve energy -conserving effect.