centos yum源是没有php的安装包，修改使用webtatic，remi的源
扩展源

rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm

php源

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

查看yum已安装的php和相关扩展

yum list |grep 'php'

卸载已安装的php和相关依赖扩展(根据上面查询的文件名适当修改)

yum remove php56w php56w-*

安装php7.1

yum install php71w php71w-fpm
yum install php71w-bcmath php71w-gd php71w-mbstring php71w-mcrypt php71w-mysqlnd php71w-odbc php71w-opcache php71w-pdo php71w-pdo_dblib php71w-pear php71w-pecl-* php71w-phpdbg php71w-xml php71w-xmlrpc

配置好nginx后重启php-fpm

service nginx restart
service php-fpm restart