The invention discloses a method for preparing a high-nickel concentrate from a low-grade red soil nickel ore, which comprises the following steps of: drying the low-grade red soil nickel ore until water content is 13 to 16 percent, crushing to ensure that the size of all particles is less than 3mm, grinding by using a high-pressure roller mill to ensure that particles with the size of less than 0.074mm account for 80 percent and specific surface area is not less than 2,000cm<2>/g, adding 15 to 20 percent of composite binder and 1 to 5 percent of coal powder, and pelletizing by using a disc pelletizer to obtain green pellets with the size of 6 to 16mm; drying and preheating the green pellets on a chain grate for water removal and solidification to ensure that each piece of pellet entering a kiln has the compression strength of over 500N; directly adding the preheated and solidified pellets into a rotary kiln, and reducing at the temperature of between 1,100 and 1,250 DEG C for 60 to 120 minutes by using pea coal as a reducing agent in a mass ratio of the reducing coal to the pellets of 0.8-1.0; and cooling a reduction product, sieving, performing magnetic separation to obtain a magnetic product, crushing, grinding, and performing magnetic separation to obtain the high-nickel concentrate, wherein the composite additive comprises the following components: Na2CO3 and CaO, iron oxide powder, the coal powder and sodium humate in a ratio of (30-60):(20-30):(20-30):(5-10). The method is high in adaptability and nickel recovery rate and suitable for mass production.