▎ 摘　　要

NOVELTY - Controllable preparation of gradient composite membrane comprises preparing precursor solution and preparing gradient composite membrane by using the strategy of dilution or concentration of the precursor solution to control the concentration of the load in the precursor solution in real time, dynamically changing at least one of precursor solutions, which directly connected to the film preparation device to obtain a gradient composite film with a continuously changing load content distribution or pre-collecting the above-mentioned different kinds of precursor solutions with continuously changing concentrations into the solution storage of the thin film preparation device to obtain a stable gradient precursor solution and combining with the thin film preparation device for and continuous gradient for controllably obtaining positive membrane. USE - The composite membrane is useful in aerospace, biomedical and green energy and national defense technology. ADVANTAGE - The composite membrane is useful in aerospace, biomedical and green energy and national defense technology.