The invention relates to a preparation method of a heat-shrinkage-resistant power battery separator. The method comprises steps as follows: discharge gas is fed into a DBD (dielectric barrier discharge) plasma reactor, the high-voltage alternating current enables the discharge gas to discharge to produce plasma, a precursor is sent into a plasma area for a reaction by the aid of carrier gas and reaction gas, a reaction product deposits on a substrate, and the heat-shrinkage-resistant power battery separator is obtained. The method is simple and easy to implement, manufacturing and production equipment is simple, shorter time is taken, preparation is convenient, and no catalyst or template is required; during preparation, energy consumption is low, pollution is low, the deposition rate is high, no other solvent is used in the separator deposition treatment process, the preparation method is an environment-friendly dry method, and the feasibility of industrial application is increased.