The invention discloses a preparation method for 1-amino-1-cyanamido-2,2-sodium ethylene dicyanide. The method comprises the following steps: adding sodium dicyanamide and reaction catalyst activated clay into a reaction solvent; increasing temperature to 120 DEG C or above 120 DEG C, dropwise adding quantitative malononitrile solution and reacting for 2-4 hours by keeping the temperature at 120-170 DEG C; performing thermal filtration on the acquired reaction solution and removing the activated clay; performing reduced pressure distillation on the acquired reaction solution and distilling the reaction solvent; reducing the temperature of the acquired reaction solution to 60 DEG C or below 60 DEG C, adding quantitative carbinol and dispersing the product; cooling the reaction solution to 20 DEG C or below 20 DEG C and filtering, thereby acquiring a crude product; re-crystallizing the acquired crude product with a mixed solvent, thereby acquiring the product. According to the preparation method for 1-amino-1-cyanamido-2,2-sodium ethylene dicyanide disclosed by the invention, the reaction yield is increased, the cost-optimal mixed solvent water and carbinol are used for refining and preparing the high-content product, the production cost is lowered and the higher economic benefit in the industrial production is acquired.