The invention discloses abietyl quaternary ammonium salt-modified organic nano imvite, a preparation method thereof and use thereof. The preparation method comprises: adding solution of abietyl quaternary ammonium salt into suspension of organic imvite at 70 to 80 DEG C under a stirring condition; and freezing and drying the mixture to obtain the abietyl quaternary ammonium salt-modified organic nano imvite. The modified nano imvite, a polyalcohol and another assistant are mixed in a certain ratio, the mixture is ultrasonically dispersed uniformly and then mixed with isocyanate, and the newly-obtained mixture is stirred by an electric stirrer for 20 to 30 minutes at a speed of 3,000 to 3,500r/min and then filled in a mould for foam moulding and aging. The abietyl quaternary ammonium salt-modified organic nano imvite flame-retarding hard polyurethane foam plastic prepared by the invention has high compression strength, tensile strength and thermal stability and flame retardance as wellas an antibacterial performance and is expected to be widely used in building, heat preservation and some special fields.