Abstract: This paper makes a preliminary approach to the relationship between mire development and palaeogeographical environment changes since the early period of middle Holocene in the east part of the Xiliaohe Plain by means of dating, X-ray diffraction of clay mineral, analyses of spore-pollen and plant residual, content and translation and transformation of chemical elements, etc. The formation and development of mire located in the ecotone and ecological transition zone are highly sensitive to the environment change. The environment changes have occurred frequently since the early period of middle Holocene which results in cycle change of formation, development, degeneration and death of mire in its development process. The close relationship was found between mire development and palaeogeographical environment change. It can be divided into six periods, i.e. the breeding and germinating development period in the early period of the middle Holocene (6400-5100a B. P.), the vigorous development period in the middle period of middle Holocene (5100-4300 a B. P.), the interruption development in the middle and late period of middle Holocene (4300-3200 a B. P.), the degeneration development period of the late period of middle Holocene (3200-2100 a B. P.), the resuscitation development period of the early period of late period of late Holocene (1100-0a B. P.). The oldest mire was formed in about 5800a B. P. in the east part of the Xiliaohe plain in the Holocene. The mire development follows the model of long period development of eutrophic mire. The Maili bog-section, Horqin Zuoyi Houqi can be considered as one of the standard section of the Holocene in the east part of the Xiliaohe Plain. The peat deposition is characterized with mult-period in this area in the Holocene.