The platform of SAS, Spike Antigenicity for SARS-CoV-2, was initiated to deal with the latest antigenicity information for SARS-CoV-2. Connecting to Global Initiative on Sharing All Influenza Data (GISAID) database, SAS can automatically collect all Spike mutants and calculate their epitope positions, epitope regions and potential antigenic resistance. Based on above, SAS produces monitoring reports on the emerging drifted mutants, and further suggests the dynamic changes of immune-protection coverage for representative mAbs. The pre-defined epitope regions include both validated and predicted epitopes. For each queried mutant, users can manipulate the antigenic clustering tree or heatmap to visualize the antigenicity similarity between query, monthly representative S and the benchmarking S proteins. SAS may help to monitor the antigenicty change and faciliate the mAb/vaccine development.