Shape-forming technology is essential for the widespread utilization of metal-organic frameworks. We developed a one-pot synthesis method for HKUST-1 monolith. HKUST-1 monolith was successfully prepared by the hydrothermal treatment of a Cu monolith in an aqueous solution of 1,3,5-benzenetricarboxylic acid, ethanol, and nitric acid without the addition of a metal source. The prepared HKUST-1 monolith showed CO2 adsorption properties comparable to those of commercially available HKUST-1 powdery crystals.