I want to use QGIS with Qt 5.But i don't know the exact relationship between Qt and QGIS.Will there some problems if i use qgis with qt5 or it will not depand on it...
QGIS 2.10 and later can be compiled against Qt 5.
Current QGIS master branch (which will become QGIS 3.0) requires Qt 5.
That means: if you download QGIS from a known place and it is labeled with a version number below 2.99, you will be running it with Qt 4. If it is labeled with a version number 2.99 (or 3.X) you will be running it with Qt 5.
Please note: it is not possible to just download QGIS and use it with another Qt version. Switching the Qt versions requires rebuilding (compile and link) the application.
Build instructions can be found here.
QGIS depends on Qt4 and does not work with Qt5, see: http://pvanb.wordpress.com/2013/04/28/building-qgis-on-ubuntu-13-04/
according to Martin Dobias on Google+ QGIS page, Dec 20, 2012:
QGIS will be moving at some point, but not for the coming release (2.0)
I've made Qt5-based QGIS on Windows successfully!!
There's a branch of the 2.4 code that can be built against Qt5 and it's available here. The plan is to merge this changes back into the trunk, but for now this is the current method.
QT is the framework that provides the 'widgets' that builds the UI for QGIS. They plan to make QT5 backwards compatible but there might be somethings that might not be compatible. The worse case scenario is that either it won't compile, run, or you find a bug where an action wont work when you click a button.
Truthfully I am not sure which version of QT QGIS is design against, but you can try. ArchLinux runs currently on QT4 as their main QT package and I have not had a problem.