由于docker默认镜像源是在国外

可替换为国内的镜像源https://www.daocloud.io/mirror#accelerator-doc

也可参考https://mirrors.ustc.edu.cn/help/dockerhub.html

[root@VM_0_13_centos ~]# curl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s http://f1361db2.m.daocloud.io
docker version >= 1.12
{

 "registry-mirrors" : ["https://docker.mirrors.ustc.edu.cn"]

}
Success.
You need to restart docker to take effect: sudo systemctl restart docker 
[root@VM_0_13_centos ~]# systemctl daemon-reload
[root@VM_0_13_centos ~]# systemctl restart docker
[root@VM_0_13_centos ~]# docker pull centos/mysql-57-centos7

按照以上操作既可以了