The boy was attacked in Wash Brook Nature Park on Tuesday, prompting an appeal to parents not to let their children walk alone in the area.
He was left "deeply distressed" and needed medical treatment.
Leicestershire Police said Ajay Jetha, from Keyham, had been charged with "numerous sexual offences" and was due before magistrates on Monday morning.
Ch Supt David Sandall, who has been leading the investigation, urged people not to speculate about the boy's identity.
"Throughout this investigation, my priority has been to safeguard the interests of the boy in this case.
"He and his family are going through a deeply distressing time and any attempt to identify him will only add to their distress."
The boy, whose age has not been released, was attacked between 15:30 and 16:00 BST on Tuesday.
A 32-year-old man has been charged over a serious sexual assault on a young boy in Leicester.