have a look at Deploying an Application on Windows. Qt Plugins
Your application may also depend on one or more Qt plugins, such as the JPEG image format plugin or a SQL driver plugin. Be sure to distribute any Qt plugins that you need with your application, and note that each type of plugin should be located within a specific subdirectory (such as imageformats or sqldrivers) within your distribution directory, as described below.
Note: If you are deploying an application that uses QtWebKit to display HTML pages from the World Wide Web, you should include all text codec plugins to support as many HTML encodings possible.
The search path for Qt plugins is hard-coded into the QtCore library. By default, the plugins subdirectory of the Qt installation is the first plugin search path. However, pre-determined paths like the default one have certain disadvantages. For example, they may not exist on the target machine. For that reason, you need to examine various alternatives to make sure that the Qt plugins are found: .Using qt.conf. This approach is the recommended if you have executables in different places sharing the same plugins. .Using QApplication::addLibraryPath() or QApplication::setLibraryPaths(). This approach is recommended if you only have one executable that will use the plugin. .Using a third party installation utility to change the hard-coded paths in the QtCore library. If you add a custom path using QApplication::addLibraryPath it could look like this: