The invention relates to a method for manufacturing a refined high cleanliness Al-Ti-B alloy, comprising the following steps of: (1) melting an aluminum ingot, and adding potassium fluotitanate and potassium fluoborate for alloying; (2) pouring a reaction by-product floating on the surface of aluminum liquid, and neutralizing with alumina powder; (3) raising the temperature of the aluminum liquid, and scattering an alumina powder layer; (4) introducing argon or nitrogen with a pipe so that a residue solution coated in the aluminum liquid floats and is neutralized; (5) measuring the hydrogen content after the solution is treated by utilizing a small bubble rotation and degassing refining technology; (6) scattering a special high temperature anti-oxidation covering agent layer in the hot state of more than 800 DEG C; (7) raising the temperature of the aluminum liquid, introducing the aluminum liquid to a filtering box body filled with an alumina ceramic filter, and carrying out online filtering treatment on the alloy aluminum liquid; and (8) finally, reducing the temperature of the aluminum liquid, discarding scruff scum, and molding by casting to produce Al-Ti-B filaments. The method can effectively separate fluoride salt and other impurities in the Al-Ti-B alloy liquid so that the impurities in an Al-Ti-B alloy refining agent are reduced, and the cleanliness is greatly improved.