An efficient diffuse reflection film comprises a reflection film body, wherein microbubbles are distributed in the reflection film body provided with a diffuse reflection coating; the diffuse reflection coating is composed of, by mass, 20 parts of butanone, 12 parts of ethyl acetate, 10 parts of acrylate resin, 1 part of isocyanate, 1-5 parts of diffusion particles with the particle diameter ranging from 20 microns to 50 microns, and 0.5-5 parts of extinction powder. A preparing method comprises the steps: A, preparing master batches of the reflection film body; B, preparing master batches of an anti-adhesive layer; C, preparing a bidirectional tension film; and D, preparing the diffuse reflection coating and performing coating. The efficient diffuse reflection white film has extremely low surface gloss and excellent diffuse reflectivity, and therefore the reflection performance is extremely good.