The invention relates to high-strength high-toughness self-leveling light aggregate concrete and a preparation method thereof. The light aggregate concrete is made of cementing materials, leveling agents, toughening materials, sand, a crude aggregate and water through mixing, wherein the cementing materials are ordinary Portland cement, glass beads and nano micro silicon powder; the leveling agents are a slump-prevention type water reducing agent and an associated thickening leveling agent; the toughening materials are an ethylene-vinyl acetate copolymer emulsion, an epoxy modified acrylic emulsion and a polyvinyl alcohol fiber; the sand is medium sand; and the crude aggregate is shale macadam ceramsite. The preparation method comprises the following steps: firstly, uniformly stirring theethylene-vinyl acetate copolymer emulsion, the epoxy modified acrylic emulsion, the nano micro silicon powder and the shale macadam ceramsite for 1 minute, leaving the mixture to stand for 3 minutes,and further stirring the mixture with the sand, the cement, the glass beads, the water, the polyvinyl alcohol fiber and the associated thickening leveling agent for 3 minutes. The light aggregate concrete provided by the invention has the characteristics of being light in weight, high in strength, free of light aggregate floating, good in flowability, high in toughness and small in shrinkage, canbe applied to large-span bridges and auxiliary structures thereof, and can be also applied to industrial and civil high-rise buildings.