Robbie Fowler, 48, last managed East Bengal FC in the Indian Super League for the 2020-21 season, and also helped as a coach at Oxford United more recently.
He started his managerial career in 2011, taking charge of Thai outfit Muangthong United for one season.
Robbie Fowler also managed Australian side Brisbane Roar between 2019 and 2020.
Al-Qadsiah posted on Twitter: "Robbie Fowler. One of the most famous players in Liverpool and the English Premier League. Coach for Qadisiyah."
Al-Qadsiah finished 11th of 18 in the second tier last season, 23 points behind the top four who were all promoted.
But they will now be hoping the Reds legend can fire them to promotion, where they would face the likes of Cristiano Ronaldo, Karim Benzema and N'Golo Kante.
Fowler, 48, took on his first job in the dugout at Thai outfit Muangthong United from 2011-12.
He then was in charge at Brisbane Roar from 2019-20 before a spell with East Bengal in 2020-21.
There has been a recent influx of big-name players in Saudi Arabia, with former Real Madrid striker Karim Benzema and ex-Premier League midfielders N'Golo Kante and Ruben Neves among those who have followed former Manchester United striker Cristiano Ronaldo to the Middle East.