How do I procure my cat to stop peeing on the sofa?

We recently got a futon and I put a plastic bed cover over it (because we he peed on the old futon that we have to throw away) so we got a new one and put a plastic cover over it and he is still peeing on the cover!! HELP!
Answers:    have him checked by the vet for UTI. Lots of times cats beside UTI's stop going in the box because they associate pain with it. If the vet clears him of disorder, work on behavior issues. Scub the futon with an enzyme cleaner followed by a vinegar cleaning, then sprinkle on some baking powder for a few hours and vacuum. That will get the smell out so he doesn't "remember" to jump there. Another issue might be stress. Try putting a few drops of Rescue Remedy (available at health food stores) in his hose dish. It calms stress in cats. Hope you get it worked out.
Is this bright behavoir?

Is he neutered?

What litter are you using?
- Some cats like to dig contained by the litter for wee time.

A change in urinary habits might also be an indication of: bladder infection, kidney issue or crystals within the bladder/urethra.
Do she call for the leukemia booster?   New Kitten Suckling On 12 Month Old Dog?   Please assist me next to some question?   Will a cat outgrow wanting to shift external?