Is the Great firewall something specific to the country or the area you live in?
Your profile page says you are located in China, so I assume you meant some government regulations prevent you from accessing Docker Hub. Have you tried opening a support ticket on Docker Hub and asking whether a Docker Hub mirror exists in China?
Update: I realize my last question doesn’t make sense if you are not able to access Docker Hub 
Update2: I found a stack overflow post that shows how to configure the docker engine to use the Chinese registry mirror: Acclerate docker pull in China/Asia - Stack Overflow