The invention discloses a gelatin composite adsorbent based technology for high efficiently removing heavy metals in water. A gelatin composite is taken as the adsorbent. The desulfurization wastewater in multiple power plants can be processed efficiently without adding separation equipment. The heavy metal ions in desulfurization wastewater can be removed high efficiently. The adsorbent is simple to prepare, the raw materials are cheap and easily available, at the same time, the separation is simple, and heavy metals in wastewater can be easily separated. The technology has the advantages that various heavy metals can be fully separated, at the same time, the separation process becomes easy, and the heavy metal separation efficiency is improved.