Abstract: There are so many copyright infringement disputes aroused by the software industry's fast development.From the legislation and judicial practice in EU and the U.S, the software's decompilation basically has become legalized;however,there still exist some copyright issues that incarnate into the field of fair-use definition.Compare to the western country's legislation,our legislation has showed conservatively,but along with the economic development,the similar cases may be more and more and the judicial application will become increasingly important.Through the comparison,we can discuss the applicable possibility from the analysis of EU and U.S relative regulations and judicial applications.