The invention discloses a novel raw-water ammonia nitrogen removal agent which comprises the following components in parts by weight: 10-15 parts of sodium phosphate, 5-10 parts of polymeric flocculation compound, 8-10 parts of diatomite, 3-5 parts of potassium permanganate, 10-15 parts of sodium hypochlorite, 5-10 parts of magnesium chloride, 5-10 parts of zeolite powder and 3-5 parts of powdered activated carbon. Compared with the prior art, the novel raw-water ammonia nitrogen removal agent provided by the invention has the following beneficial effects: (1) the novel raw-water ammonia nitrogen removal agent not only has a strong ammonia nitrogen removing effect, but also greatly reduces the dosage of follow-up agents, thereby reducing operation costs of water plants and ensuring the safety of pretreatment of drinking water; (2) the preparation process is simple, and the cost is low.