The 55-year-old, who arrived at Ravenhill in 2012, will now remain in charge of the team until summer 2015.
"My focus over the next year-and-a-half will be to finish the job that I have started and to bring some silverware back to Ravenhill," Anscombe told the club's official website.
"I have enjoyed my time at Ravenhill so far. We have made good progress, we have a great squad and some excellent young players coming through, so I am pleased to be committing for a further year."
Ulster recently secured themselves a home quarter-final against Saracens in the Heineken Cup following six wins from six games in the pool stage.