The 30-year-old man has been arrested on suspicion of GBH, Lincolnshire Police revealed today.
The attack happened at around 5pm on Saturday, and the victim, a man in his 40s, was taken to hospital having suffered serious injuries.
He remains in hospital. No further details have been released of his injuries or his condition.
Central Park was closed after the incident on Saturday, but police say it has now been re-opened to the public.
The arrested man has been remanded in custody and will be questioned in due course, police said at 9.30am today.
Police continue to appeal for witnesses and ask that anyone with any information contact them on 101, quoting incident 428 of March 28.