默认的版本太低了，手动安装有一些麻烦，想采用Yum安装的可以使用下面的方案：
1.检查当前安装的PHP包
yum list installed | grep php
如果有安装的PHP包，先删除他们
yum remove php.x86_64 php-cli.x86_64 php-common.x86_64 php-gd.x86_64 php-ldap.x86_64 php-mbstring.x86_64 php-mcrypt.x86_64 php- mysql .x86_64 php-pdo.x86_64
2.Centos 5.X
rpm -Uvh http: // mirror.webtatic.com/yum/el5/latest.rpm
CentOs 6.x
rpm -Uvh http: // mirror.webtatic.com/yum/el6/latest.rpm
CentOs 7.X
rpm -Uvh https: // mirror.webtatic.com/yum/el7/epel-release.rpm
rpm -Uvh https: //
mirror.webtatic.com/yum/el7/webtatic-release.rpm
3.运行yum install
yum install php55w . x86_64 php55w - cli . x86_64 php55w - common . x86_64 php55w - gd .x86_64 php55w - ldap . x86_64 php55w - mbstring . x86_64 php55w - mcrypt . x86_64 php55w -mysql . x86_64 php55w - pdo .
x86_64