The invention discloses a building double-layer energy-saving window structure and an energy saving method thereof. An external window unit is formed by two
layers of windows, i.e., an inner window and an outer window; one external window unit can be separately arranged, or a plurality of external window units are continuously arranged in parallel. The inner window is made from a bridge-cutoff aluminum
alloy frame material and hollow glass; a double-layer energy-saving window is provided with a cavity, and the cavity is internally provided with an electrically-lifted rotary
shutter curtain; the outer window is made from an aluminum
alloy frame material and a single layer of glass. The building double-layer energy-saving window structure can effectively reduce the numerical value of a
heat transfer coefficient of the outer window, fully utilizes the
sunlight so as to achieve an ideal energy-saving effect, can effectively reduce the influence of building outdoor
noise on the interior of a room, and can improve and adjust the indoor light environment by means of the electrically-lifted rotary
shutter curtain in the cavity so as to improve the indoor
environmental quality; the building double-layer energy-saving window structure can be flexibly installed, enriches the architecture modeling design and improves the whole quality of a building.