Do you mean using your own domain on a Medium blog? If so, that was disabled a while ago. Or do you mean cross posting the same content on Medium and your blog?

Do you mean using your own domain on a Medium blog? If so, that was disabled a while ago. Or do you mean cross posting the same content on Medium and your blog? That's tricky, how do you tell Google that it should consider your blog as the owner of the content? Otherwise you can get punished for duplicated content.