Shocking photographs of the injuries show a large wound in the officer's head.
The officer was attempting to stop a stolen vehicle, police confirmed.
North Yorkshire Police said in a statement: "Assaults against police officers and staff are never acceptable, aren't 'part of the job' and won't be tolerated."
"Our police officers and staff are people, they are fathers, mothers, sons and daughters.
"When they are attacked they become victims just like any other, but victims who have been attacked while trying to protect others from being victimised."