The invention discloses a compound for preparation of a high-strength polyolefin permeable membrane and a preparation method thereof. The compound comprises the following components in parts by weight: 35-65 of polyolefin resin, 30-60 of micron inorganic filler, 1-10 of nano inorganic filler, 0.2-0.5 of antioxidant, 0.1-1.0 of processing aid and 0.1-3.0 of coupling agent. The invention can improve the mechanical properties of the polyolefin permeable membrane through reasonable selection of the polyolefin resin and the nano inorganic filler, thereby reducing the thickness of the permeable membrane under the condition that the use requirements are satisfied. Moreover, the invention not only can fully develop the strengthening function of the nano filler, but also can obtain the permeable membrane with uniform aperture distribution and with water pressure resistance up to 100cm through the reasonable surface processing and the economical process flow. The transverse tensile strength of the permeable membrane is higher than 15MPa, the vertical tensile strength of the permeable membrane is higher than 30MPa, and the water pressure test reaches a 100cm water column, that is, the membrane can bear the 100cm water column without water permeation, breakage and the like.