环境：CentOS 7
1. 安装依赖环境
# yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel
2. 浏览器打开 https://www.python.org/ftp/python/ 查看最新的Python版本，标记为3.A.B
# wget https://www.python.org/ftp/python/3.A.B/Python-3.A.B.tgz
3. 创建Python3的目录
# mkdir /usr/local/python3
4. 解压下载文件并切换目录
# tar -zxvf Python-3.A.B.tgz
# cd Python-3.A.B
5. 执行
# ./configure --prefix=/usr/local/python3
# make && make install
6. 创建Python3的软链接
# ln -s /usr/local/python3/bin/python3 /usr/bin/python3
7. 创建Pip3的软链接
# ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3
8. 测试命令 python3 和 pip3
# python3
# pip3
安装保留了原python命令调用python2
安装完成