The invention discloses a preparation method of a waterborne micro porous waterproof and
moisture permeable film. The preparation method comprises the following steps that S1, materials are prepared,the raw materials in parts by weight are weighed in proportion: 100 parts of a waterborne
polyurethane emulsion, 5-8 parts of methylbenzene, 10-20 parts of
ammonium hydroxide, 2-3 parts of a water-proofing agent and 65-70 parts of water; S2, mixing is conducted, the raw materials weighed in step 1 are mixed to obtain a colloidal mixture; S3,
coating is conducted, release paper is evenly coated with the mixture; and step 4 is conducted before the mixture is in a solidified state after
coating; S4,
drying is conducted, the release paper coated with the mixture is sent into an oven for
drying, temperatures with at least three levels are set in the oven, the first-level temperature is 78 DEG C to 80 DEG C, the second-level temperature is 100 DEG C to 120 DEG C, and the third-level temperatureis 150 DEG C to 160 DEG C; and S5, stripping is conducted, after
drying, the release paper is stripped to obtain the waterborne micro porous waterproof and
moisture permeable film. A film product prepared by the preparation method has the functions of
moisture permeability and anti water drop, water dropping on the film surface does not expand, and meanwhile the micro porous waterproof and moisture permeable film has excellent elasticity.