Abstract: Toushe Basin is located in the central part of Taiwan Province. It is the forefront of the East Asian monsoon area in China. It is very sensitive to the response of the East Asian monsoon. It is of great scientific significance to study the paleovegetation and reconstruct the paleoclimate since the Mid-Late Holocene, and to explore the relationship between the climate and the East Asian summer monsoon. Based on the AMS14C dating and volumetric magnetic susceptibility measurements of peat-lake sediments in Toushe Basin, the vegetation changes since the Mid-Late Holocene were reconstructed and paleoclimate was reconstructed on the basis of Palynologyrecords. The results show that there are six stages since the middle and late Holocene: 6.2-6.0 cal ka BP, the climate was cool and dry, the vegetation type was subtropical evergreen broad-leaved forest; 6.0-4.0 cal ka BP, the climate was warm and humid, the vegetation type was subtropical evergreen broad-leaved forest with more tropical components; 4.0-2.2 cal ka BP, the climate was relatively cool and dry, and the vegetation type turns to subtropical evergreen broad-leaved forest; 2.2-1.9 cal ka BP, climate was warm and humid; 1.9-1.7 cal ka BP, climate was drying rapidly, forest degradation; 1.7-1.3cal ka BP, climate is warm and humid again, vegetation type is similar to modern marsh grassland. As a whole, the climate change of 6.2 to 2.2 cal ka BP is a trend from warm and humid to warm and cool and dry. This is caused by the decrease of solar radiation since activities the middle and late Holocene. The decrease of solar radiation leads to the southward of ITCZ, which leads to the weakening of the East Asian summer monsoon. After 2.2 cal ka BP, the climate fluctuates greatly, possibly caused by weakening of the summer monsoon, coupling with ENSO activities and human activities were  trengthened.

Key words: Mid-Late Holocene, East Asian, summer monsoon, paleoclimate, palynology records