A degradable EVOH high-barrier composite film, characterized in that the materials of various layers in the composite film all obtain approximately-consistent biodegradability by introducing biomass, and the additive amount of the additive master batch in the materials of each layer is controlled within the range of 0.3-15% of the total mass of the materials of the corresponding layer; the hydrophilic activity of the hydrophilic groups in the additive master batch should be greater than or equal to that of the hydrophilic groups in the materials of each layer; by adding the additive master batch, the mole ratios of the hydrophilic groups to carbon atoms of the materials of various layers tend to be consistent, namely, the bioactivities tend to be consistent, so that the degradation rates of the materials of various layers in the composite film tend to be consistent. The present invention makes contribution to obtaining approximately-consistent bioactivities and approximately-consistent biodegradation rates by balancing the mole ratios of the hydrophilic groups to carbon atoms in the materials of various layers, and the appearance, the functions and the physical and mechanical properties of a product remain unchanged.