The present invention provides an interleukin 15 fusion protein for tumor target therapy, comprising (i) IL-15 polypeptide or variants or functional fragments thereof, (ii) IL-15Ra polypeptide, or variants or functional fragments thereof, (iii) Fc structural domain, or variants or functional fragments thereof, and (iv) RGD polypeptide or variants thereof. The order for the fusion protein is RGD polypeptide-Fc structural domain-IL-15 polypeptide-IL-15Ra polypeptide. In one aspect, the fusion protein can enhance the anti-tumor effects of IL-15, and in another aspect, the fusion protein can overcome the problem of short half-life of IL-15, and can target a tumor site and act on tumor cells.
