The 28-year-old, who was voted the club’s player of the season for 2017, has signed a new four-year contract to keep him at Belle Vue until the end of 2021.
Ashurst played in all 32 of their games last season and helped Wakefield finish fifth in the Super League.
The St Helens academy product joined Wakefield from Salford Red Devils in 2015 and is excited to continue working under head coach Chris Chester.
Ashurst said: “I am really happy to have secured my long-term future here at Wakefield.
“The club has improved massively in the time I’ve been here and that showed with us narrowly missing out on the semis last season.
“I have enjoyed working under Chezzy [coach Chris Chester] and the rest of the staff and we’ve got a really good group of lads here which was a big reason I wanted to stay.
“I’m looking forward to the future and hopefully playing a part in the club building on the last couple of years and continuing to move in the right direction.”