IBM Worklight 6.0 - How to deploy Worklight Studio hybrid app in windows phone 7 device?

Is there any way to add Windows Phone device in IBM Worklight Studio for testing app there itself?
(except opening project with visual studio)

It is Microsoft Visual Studio that you should use to recognize your Windows Phone 7 device, not Worklight Studio.

In Worklight Studio you:

1. Create a new Worklight project
2. Add an application
3. Add the Windows Phone 7 environment
4. Write some code...
5. Build and deploy

In Visual Studio:

1. It is now on you to configure your device for development
2. Have it recognized by Visual Studio
3. Open the generated Visual Studio project (from step 5 above) in Visual Studio
4. And finally, build the app and run it on your device

You should read the IBM Worklight Getting Started training modules that are relevant to this environment:

• Previewing your application on Windows Phone 7.5
• General information when developing for Windows Phone 7.5

Note that starting Worklight 6.1.0 (to be released in the near future), Windows Phone 7.5 support has been removed from Worklight (remaining is Windows Phone 8 for this platform).