Hi Kundan,
I didn't realize you wanted to include the Project Priority field from the Resource Planner in your report, thanks for clarifying that information. You cannot report on the Project Planning Priority field. This is visible just in the Resource Planner and it serves as a flag for prioritizing your projects. The order of the projects in the Resource Planner is unique to you. Other users can view the same projects in the Resource Planner, but in a different order.
Additionally, there are several ways to use priorities for projects, but it's important to understand that they do not communicate with one another.
For more information regarding this topic, I recommend checking out the following Workfront One articles:
https://one.workfront.com/s/document-item?bundleId=workfront-classic&topicId=Content%2FManage_work%2...
https://one.workfront.com/s/document-item?bundleId=workfront-classic&topicId=Content%2FResource_Mgmt...