The invention discloses a method for describing electric parameters of distribution network lines. According to the method, any line can be considered as a uniform model: for any distribution network line, a lead of the distribution network line externally extends through being erected on a pole; the distribution network lines can be divided into a trunk line and branch lines, the branch lines have different lengths and directions, and secondary branch lines are possible to exist under the branch lines; the leads can have different models and lengths; segmented/branch switches are possible to exist on the leads and distributed power supplies are possible to exist on the secondary branch lines; and for the lines which for a looped network in a hand-in-hand manner, the lines can be connected through being considered as lines or a plurality of models. The invention provides the uniform model and a description method, the electric parameters of all the lines can be obtained through a same format and the storage is convenient; and when circuit parameters need to be calculated, calculation is directly carried out on matrixes without repeatedly querying lead parameters and accumulated line lengths, so that the rapid and accurate calculation of software can be realized and the calculation time is greatly shortened.