An ambulance crew called police after responding to an assault on Peveril Road, Peterborough, at around 3.24pm on Saturday.
The boy, who suffered multiple wounds to his face and head, was taken to Peterborough City Hospital.
He was later transferred to Addenbrooke's Hospital in Cambridge, where he remains in a stable condition.
Cambridgeshire Police on Saturday night detained a 24-year-old man at his home in the Dogsthorpe area of Peterborough.
Faisal Khan, of Almond Road, was arrested on suspicion of assault causing grievous bodily harm.
He has since been charged with attempted murder and possession of a knife in a public place.
He was remanded in custody and was due to appear before Peterborough Magistrates’ Court on Monday morning.