The invention discloses a surface modification pulp mixing machine and application thereof. The surface modification pulp mixing machine comprises a mixing vessel, wherein a plurality of sections of pulp mixing chambers are sequentially arranged from a pulp inlet to a pulp outlet in the mixing vessel, adjacent pulp mixing chambers are isolated with each other through a cutting disc fixed on a stirring shaft and a stirring clapboard fixed on the lateral wall of the mixing vessel, the stirring shaft is provided with a stirring impeller, and the lateral wall of the mixing vessel is provided with a stirring baffle plate. The surface modification pulp mixing machine is applied to a floatation feeding pretreatment stage in an ore dressing process flow, and through applying a high-cutting environment to ore pulp, the dispersion degree of a medicament and the adsorption effect on the surfaces of minerals are improved, the hydrophobicity differences between minerals is increased, and the flotability of the minerals is improved.