1.下载python3的包之前，要先安装相关的依赖包，用于下载编译python3：

yum install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gcc make

2.默认的centos7是没有安装pip，先添加epel扩展源

yum -y install epel-release

3.安装pip

yum install python-pip

4.用pip装wget

pip install wget

5.用wget下载python3的源码包，或者自己先下载好，上传到服务器再安装，如果网络快可以直接安装

wget https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tar.xz

6.编译python3源码包，解压

xz -d Python-3.6.5.tar.xz
tar -xf Python-3.6.5.tar

7.进入解压后的目录，依次执行下面命令进行手动编译

cd Python-3.6.5

./configure prefix=/usr/local/python3

make && make install

8.安装依赖zlib、zlib-deve

yum install zlib zlib
yum install zlib zlib-devel

9.最后没提示出错，就代表正确安装了，在/usr/local/目录下就会有python3目录

10.建立软链接

rm -rf /usr/bin/python3
rm -rf /usr/bin/pip3
ln -s /usr/local/python3/bin/pip3.6 /usr/bin/pip3
ln -s /usr/local/python3/bin/python3.6 /usr/bin/python3

11.配置镜像源

当前用户跟路径下mkdir ~/.pip touch ~/.pip/pip.conf
[global]
timeout = 6000
index-url = http://pypi.tuna.tsinghua.edu.cn/simple
trusted-host = pypi.tuna.tsinghua.edu.cn

12.验证已安装成功

python3 -V
pip3 list

13.安装依赖包

pip install -r requirement.txt

14.特别说明

不建议去掉默认的python的链接，将python3.6直接链接为python。因linux内很多默认的shell脚本走的是python2，改动后，会出现很多异常，还得手工调整linux默认脚本