Abstract: In the mire and reclaimed farmlands of the Sanjiang Plain, radiation balance, soil temperatute, and temperature and humidity of air were measured. And soil-heat flux was calculated with different methods. Through the analysis of a lot of data, the daily variations and the law of vertical distribution of microclimate factors on the bog surface were obtained. It is found that after the mire is reclaimed, the radiation balance increases, both soil temperature at different depths and air temperature of various height near the ground rise, and air humidity decreses obviously. Therefore, one should take the establishment of the artificial ecosystem of paddy, reed and fish breeding as the main developing direction of mire, at the same time, protect some mire in order to prevent the environment from getting dry, and maintain regional ecological balance.