The purposes of the study are to measure the relative importance of independent variables, to analyze relation between user satisfaction and use, and to improve the level of user satisfaction in using e-Trade system(uTradeHub). The study develops the independent variables in three dimensions(i.e the quality of system, quality of information, and quality of service), estimates the level of satisfaction on a par with these variables, and analyzes the causal relation of these variables. The major findings of the study are as follows. First, there is a significant casual relationship between the quality of system and user satisfaction, thus the hypothesis is accepted. Second, there is a significant casual relationship between the quality of information and user satisfaction, thus the hypothesis is accepted. Third, there is a significant casual relationship between the quality of service and user satisfaction, thus the hypothesis is accepted. Final, there is a significant casual relationship between the user satisfaction and use, thus the hypothesis is accepted.