CALYPSO (Crystal structure AnaLYsis by Particle Swarm Optimization) is an efficient structure prediction method and its same-name computer software. The approach requires only chemical compositions for a given compound to predict stable or metastable structures at given external conditions (e.g., pressure), thus the CALYPSO package can be used to predict/determine the crystal structure and design the multi-functional materials (e.g., superhard). The CALYPSO package is protected by the Copyright Protection Center of China with the registration No. 2010SR028200 and classification No. 61000-7500.