In this paper the various methods used for calculating the maximum possible evaporation (M. P. B.) are discussed. The M. P. E. of more than 300 stations in China, calculated with Budyko’s formula, using the component values of radiation and heat balance calculated by the authors and the other related climatological data, is analysed.It is found that both the time and space variations of M. P. E. in China are chiefly determined by the thermal condition and moisture condition. They are minimum in winter and maximum in summer. In the Eastern China the M. P. E. value dicreases with latitude from 1000 mm in south to 500 mm in Northeast. In the Western China, there is a low value region with a minimum value ’about 500mm around the Tibetan plateau, and a high value region with a maximum value about 1200 mm around the Tarim Basin in Sinkiang province. The annual range of the M. P. E. is quite small along the southeastern coast, only about 70 mm, but more than 130 mm, in the Northwestern China.