Hi Jun Zhou
Yes It is possible to modify the Port number. you can change it to another port with change in server.xml.
Just go to the path, where your Apache tomcat has installed. Ex: C:\Program Files\Apache Software Foundation\Tomcat 8.0\conf . In conf folder you will find the server.xml where you can change the port number. You can see the below image for reference, I am using 8095.
Do let me know in case of any question.