Redfearn took charge of the Belles last December and helped guide them to the FAWSL2 title last month.
The 52-year-old was the first former EFL manager to take charge of a senior female side.
And now he moves on to a Liverpool side hoping to compete at the top of FAWSL1 next season.
A statement from the Belles said: "Everyone at the Belles would like to thank Neil for his hard work and wish him every success in the future.
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"The board are in the process of appointing a new head coach."
On his new role, Redfearn said:“It is a massive privilege and real honour for me to have been appointed as manager of Liverpool Ladies.
“It is a team with big potential which should be challenging for trophies on a regular basis.
“Liverpool Football Club is a huge club and I have every confidence that we will be competing at the top end of the Women’s Super League this season. I am over the moon to have been given this opportunity and cannot wait to get started.”
Redfearn had been heavily linked with the managerial vacancy at Doncaster Rovers prior to joining Liverpool.