Vegetation is one of the most active factors of landscape and the important content of evaluation for cropland to forest.The relationship between different vegetation styles is central to ecological research.In the loess hilly region

study of vegetation characteristics is required for understanding of landscape ecological processes and restoration of cropland to forest.Spatio-temporal variance of(vegetation) species richness

diversity

evenness of cropland to forest of different vegetation characteristics in the loess hilly region are analyzed in this paper.The results showed no significant differentia between were observed in two vegetation index

expect species richness between Yan'an and Ansai and species diversity between Ansai and Wuqi come to significant differentia.Since north of forest zone in Yan'an to forest-grass zone in Ansai

vegetation index presented digressive trend and its maximal depressed extent was 17.65%.Coefficient of variance presented ascensive trend and its ascending extent was 21.49%.Since forest-grass zone in Ansai to grass zone in Wuqi

species richness index and its coefficient of variance both showed ascensive trend

but species diversity and evenness showed digressive trend and theirs coefficient of variance showed ascensive trend.Vegetation community was step by step steady after 20 years of cropland to forest and grass.