Hi @zhanwei.lee - I don't think that can be changed. The total issues is configurable in the pie chart gadget either to call out a project (and bring all the issues from this project) or take a filter query and bring all the issues from this query. But the total issues itself is not configurable to change into something else.
Have you looked at workload pie chart to see if that is of any help in your situation ? - https://confluence.atlassian.com/jira064/workload-pie-chart-report-720416073.html
For JSM June Challenge #2, share how your non-technical teams like HR, legal, marketing, finance, and beyond started using Jira Service Management! Tell us: Did they ask to start using it or...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events