The invention provides an evaluation method for effective seepage capability of a low-permeability sandstone reservoir. The method comprises the steps of step 1, testing a gas permeability Ka of a real rock core to obtain gas seepage capability of the real rock core; step 2, through a capillary pressure curve of the real rock core, establishing an unequal-diameter capillary buddle model, and calculating ideal permeability of the capillary model; step 3, according to a relationship between the film thickness and the clay content, determining the liquid film thickness of the rock core; step 4, according to the film thickness, calculating effective permeability of the capillary model; and step 5, calculating effective permeability of the rock core by utilizing flow equivalence of the real rock core and the capillary model, and judging the strength of the seepage capability of the rock core according to a ratio of the effective permeability to the gas permeability. The evaluation method for effective seepage capability of the low-permeability sandstone reservoir can quantitatively represent actual effective seepage capability of the reservoir after an outside fluid enters in the reservoir, thereby laying a foundation for reasonably and effectively developing the low-permeability reservoir.