Lithium resources are an emerging issue due to lithium ion batteries. Rubidium is also widely used in the field of energy and medicine, so it makes sense for the dual adsorption of lithium and rubidium at the same time. Cellulose nanocrystalline (CNC) is used as a biotemplate to synthesis mesoporous films, and hydrogen manganese oxide (HMO) is immobilized on a mesoporous film. Then Rb(I) ionic imprinted layer is grafted onto the surface of a mesoporous film to obtain a dual-functional mesoporous film. Dual-functional mesoporous films possess high selective adsorptions of Li(I) and Rb(I) and show excellent adsorption kinetic properties of Li(I) and Rb(I). The adsorption capacities of Li(I) and Rb(I) are 6.30 and 6.21 mg g(-1) under optimum conditions, respectively. HMO ion sieves and ionic imprinting make films demonstrating a high selectivity in the adsorption of Li(I) and Rb(I), enhancing their potential for industrial applications.