Dry storage of spent fuel is an effective way to solve the problem that spent fuel cannot be transported from some nuclear power plants in China. The dry storage canister is the key equipment of the dry storage system for spent fuel, which is used for off-reactor storage of spent fuel. Therefore, the work aims to analyze the design and key technologies of the dry storage canister for spent fuel under dry storage. The process and safety function requirements of dry storage system were analyzed and the design was carried out based on the functional requirements of interface. Then, the design scheme of component support structure and containment boundary was discussed. By analyzing the key technologies of critical safety design, from the control of spent fuel assembly spacing to the selection and layout of neutron materials, the critical safety structure able to maintain the subcritical state of spent fuel assembly was determined. Through the analysis of heat transfer mode, the comparison and selection of heat transfer medium, and the layout of heat transfer structure, the heat transfer structure of passive heat dissipation was designed, and a new structural design scheme of the interlocking form was proposed. The key technologies of dry storage system design were put forward, the design criteria of dry storage canister were determined, and the key technologies and solutions of dry storage canister design were put forward, and the final design of the dry storage canister structure was completed. The analysis on the design and key technologies of dry storage of spent fuel provides practical technical support for dry storage of spent fuel in China.