这里推荐使用Webtatic yum源

其实看官网就可以解决问题
https://webtatic.com/

为方便查看摘录一部分:

###CentOS/RHEL 7.x:###

yum install epel-release
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm

###CentOS/RHEL 6.x:###

yum install epel-release
rpm -Uvh https://mirror.webtatic.com/yum/el6/latest.rpm

Now you can install PHP 7.1’s mod_php SAPI (along with an opcode cache) by doing:

yum install mod_php71w php71w-opcache

You can alternatively install PHP 7.1’s php-fpm SAPI (along with an opcode cache by doing:

yum install php71w-fpm php71w-opcache

See the package list below for additional SAPIs and PHP extensions.