Abstract: A floor paint composition superior in resistance to oil and solvents, and in early strength. The composition is mainly composed of a synthetic resin emulsion based on an from anion copolymer obtained from the copolymerization of .alpha.-type hemihydrate gypsum, cement and ethylene unsaturated monomer. The ratio of weight of .alpha.-type hemihydrate gypsum to cement is between 80:20 and 95:5. The ratio of the solid content of the synthetic resin relative to 100 parts by weight of the mixture of .alpha.-type hemihydrate gypsum and cement is between 15 and 35 parts by weight. The anion copolymer contains at least one unit of a monomer selected from the group consisting of ethylene unsaturated carboxylic acid, ethylene unsaturated sulfonic acid and ethylene unsaturated phosphonic acid. The copolymer can include an ethylene unsaturated monomer having at least one organic silicon radical. The synthetic resin emulsion can include epoxy silane.