In recent years, mordenite molecular sieves with various properties have been successfully synthesized by template method. Although the template method has received a lot of attention, the addition of the templating agents especially organic templating agents, would increase the cost of raw materials, and could be harmful to environment. Therefore, the method without organic template is more economical and environmentally friendly. Recently, the synthesis and applications of mordenite modified by hetero-atom have getting more and more attentions, and the performance of modified mordenite molecular sieve shows better. The common methods for modifying mordenite molecular sieve include ion exchange method and impregnation method. Some researchers have synthesized monolithic iron-containing mordenite (Fe-MOR) by template-free method, which has excellent CO2/N2 separation performance and high carbon dioxide capture performance. In addition, Fe-MOR zeolite can catalytically decompose N2O into N2 and O2, which can effectively reduce the N2O content in the atmosphere. In this work, Fe-MOR zeolite was synthesized by hydrothermal method without organic template. A novel rod-cluster-shaped Fe-MOR zeolite was controllably synthesized by fine adjustment of pH and crystallization time, and its CO2 adsorption properties were investigated.