Abstract- Due to the increase of power load in the central area of big cities, the application of power cables are quickly increased. Compared with other laying method, pipeline shows some significant advantages, and also some disadvantages such as the difficulty of obtaining its temperature distribution and setting its suitable ampacity. On the basis of FEM model of temperature field of 10kV underground pipe-laid power cables, the optimization design theory is applied to obtain the optimum scheme of current distribution of cable groups. The power cables, and also to adjust the current of operating cables. The developed software is helpful for controlling the economic operation of pipe-laid power cables.