The invention relates to a preparation method of a novel mesoporous material for absorbing heavy metal ions in wastewater. The preparation method comprises the following steps of: 1, preparing a template; 2, hydrolyzing silicon source and rare-earth salt solution so as to form sol-gel, and crystallizing; and 3, removing a template agent, so as to obtain a sample. According to the preparation method, the synthetic method, which is low in cost, low in toxicity, simple, convenient and fast, is adopted, and the template agent is recovered, so that the cost is reduced, the performance of the mesoporous material is optimized; a mesoporous molecular sieve is simple in synthetic route, low in cost, and high in adsorptive property respect to the special ions in the solutions. After the mesoporous material is applied to a heavy metal ion absorption experiment, the ion concentrations of Pb2+, Zn2+, Cu2+ and Pb2+ in the solution after treatment are lower than the national drinking water standard. The mesoporous material is high in absorbing efficiency for Ag+.