With the support of RS, GIS and FRAGSTATS techniques, the landscape pattern has been analyzed quantitatively in Dianchi basin by 16 commonly used landscape metrics, based on remote sensing images of 1988, 1990, 1994, 1999, 2002 and 2008. After performance of principal component analysis (PCA) on the 16 landscape metrics, three principal components (PCs) were generalized: spatial aggregation of landscape patches, landscape fragmentation and landscape diversity. Then, the characteristics and evolution of landscape pattern in Dianchi basin have been explored at the landscape level. The results showed, that, from 1988 to 1994, the landscape fragmentation was serious and the level of diversity was fluctuant. And for some kinds of landscape patches, the integrity was much undermined, the spatial distribution was scattered and the degree of aggregation was fallen. From 1994 to 2008, the degree of aggregation between patches increased gradually. The situation of landscape fragmentation was under control. And, the land use types had a tendency towards diversification and homogenization.