The invention discloses a modeling method of a harmonic transfer network in the power collection system of a large-scale photovoltaic power plant. The method comprises the following steps that: S1, components requiring equivalent model establishment, which are involved in the harmonic transfer network in the power collection system of the large-scale photovoltaic power plant are identified; S2, equivalent models are established for the identified components; and S3, the structure of the power collection system of the large-scale photovoltaic power plant is converted into an equivalent impedance structure, and an equivalent model is established for the harmonic transfer network according to the equivalent impedance structure and the equivalent models of the components. According to the modeling method, influence on harmonic analysis results caused by cable parameters of the power collection system in the large-scale photovoltaic power plant, influence on harmonic power flow calculation results caused by the parameters of an LCL filter, and influence on the harmonic power flow calculation results caused by the cable parameters are fully considered, and therefore, the authenticity of the modeling of the harmonic transfer network is improved, and a solid foundation can be provided for the accuracy of subsequent harmonic power flow calculation.