The postman was pushed to the floor before his trolley of mail was stolen in Great Wyrley at around 11.30am on Saturday.
He was shaken up but not believed to be injured.
The incident took place in the Tower View Road and Poplar Road area of Landywood in the village.
Staffordshire Police detained three suspects shortly afterwards on suspicion of robbery and further theft offences.
They remain in custody.
The suspects are a 37-year-old man from Smethwick, a 30-year-old man from West Bromwich and a 17-year-old male from Walsall.
Inspector Mat Walker, of Staffordshire Police, said: "We want to thank the local community for their help and support which has been invaluable.
"We will provide updates as the investigation continues."