Abstract: The magnetic-axis tilt, which is the most critical indicator of the focusing solenoid, is always the focus of researchers in related research fields. In this paper, many aspects, such as optimization of field-homogenizer design, the choice of material specifications, exploration of winding technology, design of super large size dipole steering coils, and magnetic-axis measurement technique are studied using new alignment method. The technical bottleneck of tilt less than 1.0 mrad is broken through and a large size focus solenoid whose magnetic-axis tilt is less than 0.5 mrad is successfully developed.