Model Username Password
Most models (Mi / Redmi, AX series) (blank) (set on first use) Some units print a unique password on the label.
Mi WiFi Router 3 / 3G admin admin

Change the default password after logging in

Default credentials for Xiaomi routers are publicly documented, so if your router still uses one, change the admin password immediately to a strong, unique password. Leaving the default in place lets anyone on your network reconfigure the router. Many newer Xiaomi models instead ship with a unique password printed on the device label - if yours does, use that.

How to log in to your Xiaomi router

Open a browser and go to http://192.168.31.1 or http://miwifi.com, then sign in with the credentials above. Not sure which address is yours? See router login by IP. If you don't know a changed password, you can reset the router to restore the default.