1，先确认nginx安装时已编译http_ssl模块。

　　就是执行nginx -V命令查看是否存在--with-http_ssl_module。如果没有，则需要重新编译nginx将该模块加入。yum安装的一般都编译进去了。源码编译二进制包安装的可能需要重新编译，然后make，但是不需要make install。

2，查看是否已经安装SSL。openssl version -a

3，生成SSL证书

#在nginx目录下创建ssl文件夹
cd /etc/pki
mkdir nginx
cd nginx
#生成2048位的加密私钥
openssl genrsa -out server.key 2048
生成证书签名请求（CSR），这里需要填写许多信息
openssl req -new -key server.key -out server.csr
输出内容为：
Enter pass phrase for root.key: ← 输入前面创建的密码
Country Name (2 letter code) [AU]:CN ← 国家代号，中国输入CN
State or Province Name (full name) [Some-State]:BeiJing ← 省的全名，拼音
Locality Name (eg, city) []:BeiJing ← 市的全名，拼音
Organization Name (eg, company) [Internet Widgits Pty Ltd]:MyCompany Corp. ← 公司英文名
Organizational Unit Name (eg, section) []: ← 可以不输入
Common Name (eg, YOUR name) []: ← 服务器主机名，若填写不正确，浏览器会报告证书无效，但并
Email Address []:admin@mycompany.com ← 电子邮箱，可随意填
Please enter the following ‘extra’ attributes
to be sent with your certificate request
A challenge password []: ← 可以不输入
An optional company name []: ← 可以不输入生成类型为X509的自签名证书。

#有效期设置3650天，即有效期为10年
openssl x509 -req -days 3650 -in server.csr -signkey server.key -out server.crt

4、修改Nginx配置文件

# For more information on configuration, see:
#   * Official English Documentation: http://nginx.org/en/docs/
#   * Official Russian Documentation: http://nginx.org/ru/docs/

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

# Load dynamic modules. See /usr/share/doc/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;

events {
    worker_connections 1024;
}

http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 4096;

    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;

    # Load modular configuration files from the /etc/nginx/conf.d directory.
    # See http://nginx.org/en/docs/ngx_core_module.html#include
    # for more information.
    include /etc/nginx/conf.d/*.conf;

    server {
        listen       80;
        listen       [::]:80;
        server_name  _;
　　　　　#原目录名是html，是文件数据目录，修改为http，可以和https的数据目录做区分，也可以设置成一样的。　
        root         /usr/share/nginx/http;

        # Load configuration files for the default server block.
        include /etc/nginx/default.d/*.conf;

        error_page 404 /404.html;
        location = /404.html {
        }

        error_page 500 502 503 504 /50x.html;
        location = /50x.html {
        }
    }

# Settings for a TLS enabled server.
#
    server {
        listen       443 ssl http2;
        listen       [::]:443 ssl http2;
        server_name  _;
        root         /usr/share/nginx/https;

        ssl_certificate "/etc/pki/nginx/server.crt";
        ssl_certificate_key "/etc/pki/nginx/server.key";
        ssl_session_cache shared:SSL:1m;
        ssl_session_timeout  10m;
        ssl_ciphers HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers on;

        # Load configuration files for the default server block.
        include /etc/nginx/default.d/*.conf;

        error_page 404 /404.html;
            location = /40x.html {
        }

        error_page 500 502 503 504 /50x.html;
            location = /50x.html {
        }
    }

}

详细可参考以下博客：　　

https://www.cnblogs.com/bcodepod/p/15325522.html

https://cloud.tencent.com/developer/article/1151073