Abstract:Pollen analysis resulted from 111 core samples from Diaojiao (DJ) Lake Inner Mongolia have shown the highest value of total pollen accumulati6n rate was more than 20000 grains · cm-2 · a-1 and lowest was 80～90 grains ·cm-2 · a- 1. In general, the arboreal pollen was more than 50%, up to 80%, including the following families and genera: Pinus, Betula, ,Picea, Carpinus, Ouercus, Ulrnus etc. The non-arboreal pollen consist of 27 types, which mainly include Artemisia, Ephedra, Chenopodiaceae, Compositae, Gramineae, Leguminosae, Labiatae, Nitraria. Polygonaceae, Ranunculus, Thalictrurn, Umbelliferae, Caryophyllaceae and Cyperaceae etc. Fern spores, aquatic pollen and algae were also observed off and on in the DJ core. A pollen diagram, of five pollen assemblage zones was established through stratigraphically constrained cluster analysis,using the method of incremental sum of squares. It shows two peaks appearing at about 6.3 and 5.1 ka BP in the curve of total pollen accumulation rate. The first peak reflects a humid period and the second an arid period. The study indicated that Holocene climatic and vegetational changes in Inner Mongolia can be recongnized at different time scales (e. g. thousands, hundreds of years, or even much shorter time scale). In addition, the humidity in that area during those time was higher than today, with dominent climate humid-cool or humid-warm during most of the Holocene time on account of the lower vaporization and high altitude (1800 ma. s. 1. ).