A system for constructing an urban design digital sand table, the system includes the following modules. A sand table environment constructing module, configured to construct a digital environment of the urban design sand table. An element grading display module, configured to perform hierarchical management on urban design elements, and perform visual hierarchical display. A spatial indicator interpretation module, configured to articulate names, algorithms, and attributes for indicators in an indicator library of the urban design digital sand table. A spatial calculation tool module, configured to load a toolkit to calculate a selected range in the digital sand table. An offline data extraction module, configured to extract the data of the digital sand table so as to export two-dimensional or three-dimensional spatial data in an offline mode. A dynamic real-time editing module, configured to perform real-time editing operation on an urban digital design scheme loaded in the system.