Disclosed is an aluminium-zinc hot-plated steel plate having excellent weather resistance, corrosion resistance and alkali resistance, and an environmental-friendly surface treating agent therefor, wherein after the surface treatment of the aluminium-zinc hot-plated steel plate using an environmental-friendly surface treating agent consisting of the components of a matrix resin compounded from a particular solvent-free aqueous aliphatic polyurethane dispersion and aqueous polyurethane-acrylic acid copolymer, an organic silicon compound, a matrix resin curing agent, a water-soluble metal salt compound and a high-density polyethylene lubrication auxiliary etc., the formed surface-treated aluminium-zinc hot-plated steel plate has comprehensive properties of excellent weather resistance, corrosion resistance and alkali resistance, and good machine formability etc.