(B, ) utility model name: (B, a) energy -conserving door and window of bridge cut -off aluminium alloy (b) summary (b): the utility model discloses an energy -conserving door and window of bridge cut -off aluminium alloy. The window adopts aluminium gusset plate and screw fixed mounting, and position within indoor side window wrap architectural surface is hidden to aluminium gusset plate and screw, and it is pleasing to the eye to look the effect outward. Window frame and fan frame are the bridge cut -off aluminium alloy, and all install by plastic material and the compound section bar that insulates against heat of foaming polyurethane in the window frame and the well club frame outside. Open the fan and be independent thermal -insulated section bar with fixed frame, among them for the sealed structural form of elastic rubber strip. Compared with the prior art, the utility model discloses have increase of service life, improve ageing resistance and UV -resistant performance, particularly outstandingly simultaneously, two -layer plastics thermal insulation construction aluminium alloy ex -trusions inside and outside whole window frame structure is, heat insulation is better, opens to be elastic rubber strip structural form between fan and the fixed frame, and thermal transmission has effectively been cut off to effective whole window watertightness - performance and gas tightness ability of improving, has reached energy -conserving effect.