Calcium (Ca) is one of the most abundant elements on Earth, and it is easily accessible and very cheap. In comparison with transition-metal elements, Ca is biocompatible and environmentally friendly. Therefore, reactions using Ca compounds show a good prospect for large-scale production and application. During the last decade investigations on organocalcium catalysis have been unfolding. Besides conventional Ca salts with strong electron-withdrawing counter anions that may serve as Lewis acid catalysts, many Ca complexes have also been designed recently and found to be good catalysts, like transition-metal catalysts. Compared with the conventional inorganic bases such as NaOH and KOH, Ca(OH)2 was uniquely active in some reactions. Owning to the great abundance, non-toxicity, and the biocompatible features of calcium, Ca-catalyzed reactions have many applications in industry.