Centos 7.X use yum to install-php5.6.X

1. Check now php package

yum list installed | grep php

2. if there have any php, deleate it first.

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 

3. Configure EPEL source

yum install -y epel-release
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

4. Configure remi source

rpm -ivh http://rpms.famillecollet.com/enterprise/remi-release-7.rpm

5. Install php5.6.x

yum install --enablerepo=remi --enablerepo=remi-php56 php php-opcache php-devel php-mbstring php-mcrypt php-mysqlnd php-phpunit-PHPUnit php-pecl-xdebug php-pecl-xhprof

6. install php-fpm

yum install --enablerepo=remi --enablerepo=remi-php56 php-fpm 

7. Configure boot service

systemctl restart php-fpm
systemctl enable php-frm

8. Check if the installation is successful

ps -ef | grep php
netstat -anp | grep 9000

9. restar service

sudo systemctl restart httpd
sudo systemctl restart php-fpm
service httpd restart