This study aims to analyze the behavior of the use of Information Systems in registered taxpayers at the Palembang Middle Tax Service Office through the Unified Theory of Acceptance and Use of Technology. Specifically the purpose of this study was to examine trust in government, hedonic motivation, and social influence on the Behavior Intention and User Behavior of e-faktur and test Behavior Intentions towards User Behavior of e-faktur. This research is Quantitative Descriptive Research. The sampling method is proportional stratified random sampling method. The number of samples was 282 respondents are director and accounting major in company who registered in Middle Tax Service Office Palembang. The method in this study is statistics using SmartPLS 3.0. The results of this study indicate that trust in government has a significant effect on Behavior Intention whereas behavior does not have an effect as well as Hedonic Motivation which has a significant positive effect on behavioral intentions while behavior does not affect. Social Influence does not have a significant effect on the Behavior Intention and User Behavior of e-faktur. As well as Variable Intentions of Behavior towards User Behavior e-faktur has a significant effect. In the next study we suggested adding gender, age, experience and voluntary variables.