The boy had cycled into the play park at the rear of the Sainsbury’s Garage shortly after 7.30pm on Wednesday.
A youth, who had previously been in the area of KFC with three or four others, approached and assaulted him.
He then stole his white hybrid Beartrack bicycle, which is worth around £200.
The victim sustained a minor facial injury, which did not require medical attention.
The suspect is described as white, 15-17 years old, 5ft 6-7 inches tall, with a skinny build and dirty blonde hair.
He was wearing a pale blue t-shirt, grey jogging bottoms, and using a child’s scooter.
He was last seen heading in the direction of South Groathill Avenue.
DC Joyce Gunderson of Corstorphine CID said: “There were a number of people in the area of the play park at the time of the robbery, and we’d appeal for anyone who witnessed this to come forward.
“We’d also urge anyone who recognises the suspect’s description, or who has information on the whereabouts of the bike, to get in touch.”
Anyone with information is asked to contact Police Scotland on 101 or contact Crimestoppers anonymously on 0800 555 111.