Unknown offenders entered the premises on Thanet Road at some time between 4am and 4.30am on Saturday 24 December 2011.
Fire investigators have confirmed the blaze was started deliberately in the main bar area, causing a significant amount of damage.
Extensive police enquiries have been ongoing in and around the premises.
Officers are also requesting assistance from the local community.
PC Olly Ingham, of the York Safer Neighbourhood Team, said:
I am appealing for any information that could assist the investigation and, specifically, to help identify possible suspects involved in the arson.
If anyone was in the Thanet Road area in the early hours of Saturday 24 December and recalls seeing any suspicious behaviour near the former Turf Tavern pub, please contact the police or Crimestoppers as soon as possible.
If you can assist the investigation, please call North Yorkshire Police on 101, select option 2, and ask for PC Olly Ingham.
Information can also be passed on to Crimestoppers by calling 0800 555 111. Please quote reference number 12110215953.