Two men hit the man in the face before kicking and hitting him in the head and body after he fell to the floor during the attack in Bradford Road in Fartown, Huddersfield.
The victim suffered serious facial and head injuries.
The attack happened just before 2pm on Saturday August 5, but police only released details today.
Police want to speak to two men in connection with the incident.
The first is described as Asian and around 24 years old. He was 6ft tall, of medium build and with short hair.
He was wearing a dark hooded top with the hood up with the peak of a baseball cap showing.
The second man is described as Asian, around 25 years old, around 5ft 5in tall and of a stocky build. He was wearing a cap and T-shirt.
DC Kris Roberts of Kirklees CID, said;: “This happened at a busy time of the day on a busy road and I would appeal for anyone who witnessed it who hasn’t yet come forward to call police on 101 quoting crime reference 13170359616 or the independent crime fighting charity Crimestoppers on 0800 5515111."