The invention relates to a method for synthesizing surface molecular engram materials, in particular to a method for preparing phenol molecular engram polymers on the surface of silica gel, which solves the problems in the prior surface molecular engram polymers of low molecular weight of functional macromolecules, low content of functional groups, low grafting percent of engram materials and so on. The method comprises the following steps: firstly, the silica gel is activated, reacts with a coupling agent, and reacts with a polymine aqueous solution; secondly, the surface of the silica gel is chemically grafted with polymine to prepare a grafting material PEI/SiO2; thirdly, the grafting material PEI/SiO2 which absorbs template molecules to be balanced is added into an ethanol aqueous solution of a crosslinking agent for reaction; and fourthly, reacted materials are repeatedly washed by a hydrochloric acid for removal of the template molecules, washed by distilled water to neutralization, and subjected to vacuum drying. The preparation process is simple, and the silica gel surface engram materials prepared have high absorption capacity and superior absorption selectivity on the template molecules, have actuating locus inside silica gel surface polymer films, have small diffusion resistance and quick mass transfer speed, and are easy to achieve absorption equilibrium.