Paralleling existing cables with new is an effective way to attain the lowcost capacity expansion, which can make a full utilization of existing cable's transmission capacity. However, due to the difference in coupling effects among parallel cables, the load current may be unevenly distributed to reduce the load capacity utilization. On the background, a load distribution calculation method of parallel cables is proposed in view of the the basic equations of multiloop electromagnetic coupling between cable conductors and metal sheaths. Then the load capacity utilization of parallel cables with different layouts and phase sequence arrangements are analyzed, and application suggestions of phase sequence optimization of parallel cables are given. At last, the analysis conclusion is verified by a numerical simulation. The results show that the optimized phase sequence arrangements can improve the load capacity utilization of parallel cables effectively and take full advantages of the transmission capacity of cables.