The purpose of the study is to establish a successful the national tax service electronic document system and suggest an application method by investigating relationships among perceived availability, perceived usefulness and system acceptance suggested by Technology Acceptance Model(TAM). As a result, perceived availability and perceived usefulness were playing roles as mediums on the process of accepting an tax electronic document system, and information quality of the electronic document system turned out to influence on perceived availability and perceived usefulness. And perceived availability turned out to influence on perceived usefulness. This suggests that the more tax officials feel comfortable in using an tax electronic document system, the more useful they perceive it is.