The invention discloses a method and system for preparing carbonyl nickel powder through laterite nickel ore. The method includes the steps that firstly, the laterite nickel ore, reducing coal and additives are mixed for pelletizing; secondly, mixed pellets are reduced and molten so that metallized pellets can be obtained; thirdly, water quenching, ore grinding and magnetic separation are performed on the metallized pellets so that nickel and iron powder and tailings can be obtained; fourthly, the nickel and iron powder makes contact with carbon monoxide and sulfur-containing gaseous compounds so that first gaseous mixtures containing carbonyl nickel, carbonyl iron, carbon monoxide and sulfur-containing gaseous compounds and iron powder can be obtained; fifthly, the first gaseous mixtures are purified so that gaseous carbonyl nickel and second gaseous mixtures containing sulfur-containing gaseous compounds and carbon monoxide can be obtained; and sixthly, the gaseous carbonyl nickel is decomposed so that the carbonyl nickel powder and carbon monoxide can be obtained. According to the method, the low-price laterite nickel ore can be effectively utilized to prepare the high-purity carbonyl nickel powder, and therefore production cost can be remarkably reduced.