Abstract: Autopolyploidy is more common in plants than traditionally assumed. In order to master the research progress of autopolyploidy and get to know the research emphasis and weak link, the author analyzed the research results at home and abroad, introduced the different types of polyploidy and the changes in gene expression in autopolyploidy, including silencing, activation, and altered expression of genes and discusses the molecular mechanisms of these changes. Furthermore we also reviewed the evolution consequence of autopolyploidy. In contrast to the additive value of genome size in typical autopolyploids, nuclear DNA amount in cytologically diploidized autotetraploids exhibits considerable genome downsizing. The limited evidence currently available suggests that autopolyploids neither experience strong genome restructuring nor wide reorganization of gene expression during the first generations following genome doubling. Biogeographic and ecological surveys point to an association between the formation of autopolyploid lineages and environmental change. Autopolyploidy has received little attention compared with allopolyploidy. The systematic studies at different levels on genome size and gene expression patters in utopolyploidy are needed. It forecasted the importants of autopolyploidy in crops breeding and agricultrure in the future.