The invention discloses a starch-based super-absorbent resin environment friendly slow-release fertilizer and a preparation method thereof. The preparation method comprises the following steps: (1) adding starch, boiling water, acrylamide and N,N-methylene-bisacrylamide into a two-roll internal mixer, mixing, banburying, cooling, adding ceric ammonium nitrate, mixing, banburying, adding sodium hydroxide, mixing, banburying to obtain a crude product, soaking to absorb water, washing, drying, grinding, and screening to obtain starch-based super-absorbent resin powder; (2) uniformly spraying an ethanol mixed solution of ethyecellulose and stearic acid onto the surface of urea granules, and drying; and (3) wetting the granules obtained in the step (2) by using a mixed liquor of ethyecellulose and stearic acid, coating the granules with the powder obtained in the step (1), and drying to form a starch-based super-absorbent resin film. In soil with water content being 30%, the potato starch-based super-absorbent resin environment friendly slow-release fertilizer releases 60% of urea within 96 h.