1、进入yum源文件目录命令：cd /etc/yum.repos.d/
2、先备份一下以免出错后无法补救命令：mv ./CentOS-Base.repo ./CentOS-Base.repo.backup这段命令的四歹吭毳意思是将CentOS-Base.repo 文件重命名为CentOS-Base.repo.backup
3、然后准备下载CentOS-Base.repo文件命令：curl -Ohttps砜实蛰斓://mirrors.aliyun.com/repo/Centos-6.repo这将会把url连接的文件下载到当前的目录
4、重新加载命令：yum clean all命令：yum makecache
5、如果还是无法使用请使用命令：cat /etc/yum.repos.d/CentOS-Base.repo来检查是否与第6步的代码相同，如果不相同则修改代码与下面相同
6、# CentOS-Base.repo## The mirror system uses the connecting IP address of the client and the# update status of each mirror to pick mirrors that are updated to and# geographically close to the client. You should use this for CentOS updates# unless you are manually picking other mirrors.## If the mirrorlist= does not work for you, as a fall back you can try the# remarked out baseurl= line instead.##[base]name=CentOS-6.10 - Base - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos-vault/6.10/os/$basearch/gpgcheck=1gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6#released updates[updates]name=CentOS-6.10 - Updates - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos-vault/6.10/updates/$basearch/gpgcheck=1gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6#additional packages that may be useful[extras]name=CentOS-6.10 - Extras - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos-vault/6.10/extras/$basearch/gpgcheck=1gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6#additional packages that extend functionality of existing packages[centosplus]name=CentOS-6.10 - Plus - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos-vault/6.10/centosplus/$basearch/gpgcheck=1enabled=0gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6#contrib - packages by Centos Users[contrib]name=CentOS-6.10 - Contrib - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos-vault/6.10/contrib/$basearch/gpgcheck=1enabled=0gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6