The invention discloses a method for synthesizing high-purity hexagonal columnar silicon dioxide nanoporous material, which comprises dissolving template agent tetradecyltrimethylammonium bromide in deionized water at 27°C, stirring until the solution is clarified, and then adding Ammonia solution with a mass fraction of 25-28%, after continuing to stir for 10 minutes, add tetraethyl orthosilicate dropwise, stir while adding, the molar ratio of tetraethyl orthosilicate and template agent is 1:0.152, the mixture is in React at 27°C for 1 hour, and control the pH value of the reaction mixture at 10.6-10.8; put the reacted solution into a hydrothermal reaction kettle, then place the hydrothermal reaction kettle in a blast oven to dry, filter and wash to obtain a solid powder , drying, putting the dried sample into a tube furnace to calcinate to remove the template agent, and obtain hexagonal columnar nanoporous silica materials, all of which are hexagonal columnar and uniform in size.