According to the principal plant of peat formation, the peat-bog is divided into two types. One is low-moor in which principal plants of peat formation are herb and woody plants. The other is high-moor in which principal plant is sphagna. The climate only suitable to the development of low-moor is named the low-moor peat formation climate, the climate suitable to the development of both high-moor and low-moor is named the high-moor peat formation climate.The paper has counted T and K values (from 1961 to 1970) from 517 meteorological stations throughout the world and established ail equation of the water and heat system for peat formation, i.e. Z=5.7K+12.8-T, regarding daily average temperature in the period in which the temperature equals 10℃ more orless (T) as heat index and humid coefficient by M. H. as water index.