Ok. I found solution.
Documentation says

set INCLUDE=%INCLUDE%;c:\oracle\oci\include
set LIB=%LIB%;c:\oracle\oci\lib\msvc
cd %QTDIR%\src\plugins\sqldrivers\oci
qmake oci.pro
nmake

If you are not using a Microsoft compiler, replace nmake with make in the line above.

but make or nmake didn't work for me. Because I have not installed Microsoft Visual c++ on my machine.

I made instruction how to do this:

1 . At first don't forget to install qt sources. During the installation check Sources checkbox.

2 . then download and install oracle client win32_11gR2_client.zip. choose Runtime option during installation.(even if you are using 64 bit os download 32 bit version on oracle client). It creates c:\app\user\product\client_1... directory

3 . then open qt minGW command line(start ->all programs -> qt[version] -> [version] -> MinGW [version] -> Qt [version] for Desktop MinGW [version]) and move to the oci source folder:
cd C:\Qt\Qt[version][version]\Src\qtbase\src\plugins\sqldrivers\oci

4 . then as documentation says include OCI(Oracle call interface) path and library:
set INCLUDE=%INCLUDE%;c:\app\user\product[version]\client_1\oci\include
set LIB=%LIB%;c:\app\user\product[version]\client_1\oci\lib\msvc

5 . compile oci driver by executing these two lines:
qmake oci.pro
mingw32-make
it will creates two .dll files for you qsqloci.dll(release version) and qsqlocid.dll(debug version)

6 . last step is to copy these two files into qtcreator installation folder. go to the:
C:\Qt\Qt[version][version]\Src\qtbase\plugins\sqldrivers
and copy these files into:
C:\Qt\Qt[version][version]\mingw[version]\plugins\sqldrivers

and you are ready to go. to check connection try this code:

#include <QCoreApplication> #include <QtSql> #include <QDebug> int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); QSqlDatabase db = QSqlDatabase::addDatabase("QOCI"); db.setHostName("MY_IP_OR_HOST_NAME"); db.setDatabaseName("XE"); db.setUserName("test"); db.setPassword("test_password"); if (!db.open()) { qDebug() << db.lastError().text(); } else{ qDebug() << "Wow opened"; } return a.exec(); }