This chapter explores the problem of decoupling distribution networks through an improved distributed parametric long-line decoupling method. The traditional long-line decoupling method has certain limitations when applied to the distribution network, mainly due to the short-line characteristics in the distribution network, which cannot fully utilize the transmission delay decoupling. In response to this problem, this chapter proposes an improved line decoupling method. This improved method introduces compensation capacitance to increase the wave propagation time without changing the line length, thereby realizing the decoupling of lines in the distribution network. And by building a model for simulation analysis, the effectiveness of the method is verified, providing new ideas and methods for solving the decoupling problem of distribution networks.