There are two ways to use Jinja2 as Tornado’s default template engine:

• Inherited from mixed TemplateRendering class, and rewrite tornados’s render() function
• Set Jinja2 template loader as the default template loader while initialize Application

For implemention 1:

Please refer to: Using Jinja2 as the Template Engine for Tornado Web Framework

For implemention 2:

Please refer to: 在Tornado中使用jinja2模版引擎的简单方法