We don't have a direct connection with Mi band but you can connect it through Google Fit so we can get the information of your workouts.
Open Mi Fit app, Menu > Accounts > Sync with Google Fit
Choose your Google Account and tap OK, then you are ready to sync with Google Fit
Launch Google Fit app, Settings > Apps connected > make sure Mi Fit is shown there
Go to Google Fit main screen pull down the page to refresh you should see it will sync from your Mi Fit app
Then you connect Google Fit in WeFitter and you have it!