Abstract: According to magnetic field properties and the eddy currents in AC dipole magnet, magnet design and the thermal simulation are performed by the electromagnetic field analysis software and the schemes of key technology are determined. The Rogowski curve and the harmonic chamfering method are applied to improve the magnetic field quality. Slit arrangement on the end plates of the dipole can cut down the eddy currents effectively and lessen the temperature rise. Coils of dipole magnet are made of Al-stranded conductors for the reduction of AC eddy losses. The measurement results and the temperature test of the prototype magnet are described and discussed. The magnetic fields of the prototype meet the requirements and the temperature rise is in the safety range.