The invention discloses a method for preparing a flue-cured tobacco float breeding matrix by using wheat straws and a flue-cured tobacco float breeding nutrient solution. The method comprises the following steps of: pre-treating the wheat straws, and performing mixed piling-up fermentation treatment on the pre-treated wheat straws and pig manure, or chicken manure, lime, soil and the like so as to prepare the flue-cured tobacco breeding matrix, wherein the raw materials replace non-renewable peat, so the effects of low cost, high quality and sources; the piling-up fermentation temperature is over 60 DEG C, and the piling-up fermentation can last for more than 15 days, so that pathogenic bacteria can be killed effectively, and the disease and pest spreading can be prevented; the obtained breeding matrix is loose and porous, beneficial to growth of root systems of tobacco seedlings and high in water and fertilizer keeping capacity; the nutrient solution matched with the flue-cured tobacco float breeding matrix is complete in nutrition, and reasonable in ratio, saves fertilizers, and reduces the cost; growth conditions and agricultural indexes of the tobacco seedlings bred by using the matrix and the nutrient solution disclosed by the invention are equal to those of tobacco seedlings bred by using a peat matrix.