The invention relates to a preparation method for polymer matrix micron / nanometer packing filling modification compounding premix particles. The preparation method comprises the following steps: dissolving a water-insoluble polymer matrix into a first water-soluble solvent to obtain a homogeneous polymer solution; dispersing the micron / nanometer packing into a second water-soluble solvent, and conducting stirring, heating, and ultrasonic treatment, adding a solubilizer or a coupling agent so as to obtain homogeneous micron / nanometer packing dispersing liquid; adding the homogeneous micron / nanometer packing dispersing liquid into the homogeneous polymer solution, and mixing uniformly to obtain a homogeneous solution system solution; dropwise adding the homogeneous solution system solution into a container filled with deionized water, wherein the dropwise-added liquid is rapidly coagulated into round particles with uniform particle diameters; collecting the round particles in the container and cleaning repeatedly; drying to obtain the polymer matrix micron / nanometer packing filling modification compound premix particles. According to the method provided by the invention, the method is simple, the cost is low, the agglomeration of the nanometer packing in the polymer matrix can be reduced effectively, the infiltration adsorption effect of the polymer matrix on inorganic packing is improved, the interface bonding strength of the polymer matrix and the inorganic packing is enhanced, and the filling modification effect is improved.