Unfortunately direct products/reviews mapping is not possible between Magento & Ebay but this is possible via various numerous methods.
The first is to use eBay FileExchange(http://pages.ebay.co.uk/file_exchange/) to make an export from eBay including products reviews and then put your data in Magento supported product import file format and then go for manual import. OR you could hook up to the eBay API and download them programmatically integrated with Magento.
Beside this, there are few extensions in Magento connect market place for this task but quite expensive (some can import directly into Magento). Just search for "eBay" in Magento connect. Hope that helps!
Thanks for your answer. I have API and user ID, so is it possible to show reviews on Magento with the help of them?
Yes, you may need to setup a custom module in Magento and write some code to handle the request data that are coming inwards from Ebay to Magento using the API's you have. If you need any help reference, let me know.