访问http://yum.pgrpms.org/reporpms/repoview/letter_p.group.html，下载并安装和当前系统对应的rpm文件。
wget https://download.postgresql.org/pub/repos/yum/9.5/redhat/rhel-7-x86_64/pgdg-centos95-9.5-3.noarch.rpm
rpm -Uvh pgdg-centos95-9.5-3.noarch.rpm
cd /etc/yum.repos.d
vi CentOS-Base.repo
修改原始的yum仓库配置，在[base]和[updates]部分的尾部追加exclude=postgresql*用以取消从默认仓库安装和更新PostgreSQL。
yum install postgresql95-server.x86_64 -y
systemctl postgresql-9.5 initdb
systemctl status postgresql-9.5.service
su - postgres
psql
ALTER USER postgres WITH PASSWORD 'passwd'
\q
systemctl restart postgresql-9.5.service
vi /var/lib/pgsql/9.5/data/pg_hba.conf
修改客户端认证配置文件，将METHOD由默认的ident改为md5
systemctl restart postgresql-9.5.service
安装postgis
yum search postgis
yum -y install epel-release
yum install postgis2_95-client.x86_64 -y
Cheers ！