  Longitudinal polarization is an important design aspect of the future 100
km-scale Circular Electron Position Collider (CEPC). Spin rotators are needed
in CEPC collider rings to make the beam polarization along the longitudinal
direction at the interaction points (IPs). This paper focuses on the design of
spin rotators for CEPC at Z-pole (45.6 GeV). The design of spin rotators in
CEPC at Z-pole is based on solenoid magnets and horizontal bending magnets
sections. The coupling of transverse motion introduced by solenoids is
compensated with quadrupole lenses. Adjustments have been made to the layout to
implement the spin rotators into the collider rings.Longitudinal polarized beam
can be achieved at the IPs with the spin rotators. High degree of polarization
is attainable, while the effect of spin rotators on orbital motion is
acceptable. The detailed simulation results will be presented.A solenoid-based
spin rotator configuration is designed and integrated into the CEPC collider
ring lattice. According to the simulation results, the polarization
requirements can be satisfied.
