Abstract: Abstract: Transient expression system was a quick and efficient method to detection foreigner proteins expression in plant cell during recent years. This method has been gradually applied to various biological studies. Plant cell transient expression system has been as a new way to convenient and efficient studying promoter activity, gene functions and proteins localization in cell. In this paper, we concluded processes of how to establish and develop the plant transient expression system, as well as we summarized applications and biological significance of this system according to recent years’ research. Meanwhile we also denoted some deficiencies which still exist in the system. Base on these deficiencies, some reasonable recommendations are provided. At the end, we prospected applications of transient expression system on molecular cell biology, proteomics and virology.