In this paper, the optimum outrigger locations of the outrigger-braced structure are studied by considering the influence of the core-wall width and structural asymmetry. The axial forces in the columns are taken as unknowns, and the compatibility equations of the columns' axial deformation are formulated in terms of the axial forces. Then, the equations governing the optimum locations of the outriggers are formulated to minimize the top drift of the core wall. After that, the parametric analysis on the optimum locations of outriggers, drift-reduction efficiency, and moment-reduction efficiency in the base of the core wall are conducted numerically. The influences of different structural parameters on the optimum locations of outriggers, drift-reduction efficiency, and moment-reduction efficiency in the base of the core wall are all discussed. The change of optimum outrigger locations with the increase of ω is obviously when r=2 or η=0. For the structure with a larger core-wall width, a smaller number of outriggers can be adopted regarding the drift or moment-reduction efficiency. For instance, the drift or moment-reduction efficiency of the structure with one outrigger when η=0.5 is close to the drift or moment-reduction efficiency of the structure with two outriggers when η=0.25. Some results are presented for reference in the preliminary structural design of asymmetrical outrigger-braced structures with limited core width.