Abstract: The cracks by temperature of multi-storey building are one of common dangers. The cracks not only impair the beauty of buildingr, result in disease of buildings such as seepage,weakn its strength, rigidity and whole stability in varying degrees, but also made users unsafe.Based on theoretical analysis and quantitative calculation on reasons of cracks by temperature,the inevitability of cracks and some technical measures to be taken in practice are pointed out.