Harmonics cause serious harm to the power grid. As the network structure becomes more complex

problems of harmonic pollution brought about by resonance have been increasingly highlighted. In order to gain an insight into the resonance in the network

this paper presents an analytic method of harmonic amplification based on the singular value decomposition theory. The main information on the transfer function matrix between harmonic excitations and responses is extracted

which can be used to investigate the characteristics of the node voltage and branch current harmonic amplification in the grid. The theoretical analysis and the results of case studies have verified the effectiveness of the proposed method. This work is supported by National Natural Science Foundation of China(No. 51622702).