The invention discloses a preparation method for a negative ion emission needle. The method adopts the following steps that step 1, an ingot blank is prepared, wherein the chemical components of the ingot blank are niobium, titanium and graphene, the composite of the niobium, the titanium and the graphene is added into an electron beam melting furnace for smelting, after full and uniform stirringis carried out, casting is carried out to form the ingot blank, and the temperature is cooled to the room temperature; step 2, forging and heat treatment are carried out, wherein the ingot blank is cut into alloy bars, rotary forging, hot pressing, cold pressing are sequentially carried out to prepare an alloy plate with the thickness of 0.1 mm, and the alloy plate undergoes annealing treatment, and then is cooled to the room temperature; step 3, machining, wherein the alloy plate is divided into a plurality of alloy rods, and the alloy rods are machined into the emission needles. and step 4,surface treatment is carried out, wherein gold plating is carried out on the surfaces of the emission needles, and a gold plating layer is formed on the surface of each emission needle. The emission needle is excellent in conductivity, large in negative ion release amount and long in distance, the generated oxygen negative ion concentration is high, and in addition, the gold plating layer on the surface of the emission needle effectively reduces the loss of the emission needle, and prolongs the service life of the emission needle.