Before you can connect Google Home with Smartmi smart devices, you need to follow these steps:
1.Download "Mi Home" app from Google Play or App Store.
2.Sign up or sign in with your Xiaomi account.
3.Setup the device with your "Mi Home" app, and make sure you can control it in the app.
4.Open Google Home app, search "Smartmi Family" Action and enable it by signing in with the same ID you used in "Mi Home" app.
5.After the setup is finished, you can control the device with Google Home.
Devices compatible with Google Home: Smartmi Air Purifier