The victim, a 21-year-old man, was walking along St Mary's Butts outside Burger King towards Broad Street at about 2.30am on Thursday (17/8).
The victim then became embroiled in an altercation with another man.
During the altercation, which took place in the middle of the road, the victim was punched several times causing him to fall to the floor.
Investigating officer, Detective Constable Rosie March of Force CID based at Reading police station, said: “The victim was taken to hospital where he is currently being treated for a fractured skull and a bleed on the brain.
“The offender is described as a white man, slim, about 6ft, in his late teens to early twenties. He was wearing a black baseball cap, a light coloured vest and dark skinny jeans. He was carrying jacket in his hand.
“If you saw the incident or have any information that might assist our investigation please contact police as soon as possible. You can do this online, at a police station or by calling 101 quoting reference number 43170244134.
“If you do not want to speak directly to the police you can contact the independent charity Crimestoppers anonymously on 0800 555 111. No personal details are taken, information is not traced or recorded and you will not go to court.”
Notes to editors
A 20-year-old man from Reading was arrested on suspicion of ABH. He has been released under investigation.