The Thames Valley Police officer died in Berkshire last Thursday after being dragged along the road by a vehicle.
Jed Foster, aged 20, of Reading, has been charged with his murder and the theft of a quad bike.
He will appear at Reading Magistrates' Court on Tuesday.
Nine other people who were arrested at the same time as Mr Foster have been released on bail until September 13.
Chief Crown Prosecutor, Jaswant Narwal, said: "Following the death of PC Harper in Berkshire, the Crown Prosecution Service has today authorised Thames Valley Police to charge Jed Foster, 20, with murder and the theft of a quad bike.
"We will offer to meet with PC Harper's family to explain the basis of the decision we have made following a lengthy review of the evidence available.
"May I remind all concerned that criminal proceedings against Mr Foster are now active and that he has a right to a fair trial. It is extremely important that there should be no reporting, commentary or sharing of information online which could in any way prejudice these proceedings."