A method for extracting nickel-cobalt-manganese from laterite nickel ore by acid leaching includes the following steps: firstly, subjecting the laterite nickel ore to crushing and a physical separation treatment to separate out chromite and first tailings; then, subjecting the first tailings to a staged concentration treatment to obtain a first ore pulp; then, subjecting the first ore pulp to an atmospheric pressure acid leaching treatment to obtain a second ore pulp; then, subjecting the second ore pulp to microwave treatment; and finally, subjecting the second ore pulp to a solid-liquid separation treatment to obtain a tailing residue and leaching solution containing nickel-cobalt-manganese. The method cannot only effectively reduce the entry of chromium metal into the leaching solution through physical sorting, but also promote the leaching of nickel-cobalt-manganese through pulp adjustment and microwave treatment.