The invention discloses a nano silica-modified core-shell acetic acrylic emulsion flame-retardation high-speed cigarette nozzle connecting adhesive and a preparation method thereof. The method employsa core-shell emulsion polymerisation method, the butyl acrylate monomer and iso-octyl acrylate-modified acetic acrylic emulsion adhesive are synthesized, the emulsion particles have a core-shell structure having a hard core and a soft shell, persistent adhesivity of the adhesive is guaranteed, film forming temperature is obviously reduced, and primary viscosity is increased; iso-octyl acrylate induced in a shell layer substitutes partial butyl acrylate, the primary viscosity is further increased, and the emulsion viscosity is reduced; a fire retardant and nano silica are introduced into the polymerization process, compatibility with a polymer is increased, dispersion is uniform, so that the acetic acrylic emulsion has better water proofness, stain resistance, and solvent resistance, the prepared core-shell acetic acrylic emulsion is used as the nozzle connecting adhesive, through testing by a M5 cigarette maker, sealing degree of cigarette loading is high, bonding effect is good, andthe flame-retardation self-extinguishing character is obvious.