In order to study power cable of different arrangements for same-phase parallel multi-cable, ampacity calculate mode of the same-phase parallel multi-cable is set up by using COMSOL multiphysics finite element analysis software and MATLAB; For the four typical layouts, sub-cable load current and ampacity of cable groups are calculated and analyzed, and the phase sequence of the cable is optimized by genetic algorithm based on the maximum ampacity of the cable groups. The results show that cables are arranged in a regular triangle with a higher ampacity than horizontal arrangement, and the cable loops adopt the longitudinal arrangement mode with a higher ampacity than the horizontal layout; For the cables of the same arrangement, the smaller the uneven distribution of the load current of the sub-cable, the larger the ampacity of the cable groups; The optimal phase sequence ampacity analysis shows that the optimal cable arrangement is mode 4 (cable loops longitudinal arrangement, cable triangle arrangement), and the optimal phase sequence is ABC-BCA-ABC-BCA.