With the rapid growth of installed photovoltaic (PV) generation capacity, the influence of harmonics in PV power stations on power system stability has become more and more prominent, making harmonic mitigation a key issue for ensuring secure grid operation. This paper systematically summarizes the harmonic generation mechanisms, classification methods, modeling techniques, analysis approaches, and mitigation strategies for PV power stations. In the mechanism analysis, attention is paid not only to the dominant role of grid-connected inverters, but also to the multi-source coupling characteristics involving auxiliary equipment within the station and background harmonic excitations. On modeling methods, the advantages, disadvantages, and applicable scenarios of mechanism-based modeling, data-driven modeling, and hybrid modeling are compared, highlighting the application potential of hybrid modeling under complex working conditions. In terms of harmonic analysis, measurement-based and simulation-based approaches are distinguished, and suitable combinations of analysis methods are proposed for different scale PV power stations. Harmonic mitigation technologies are discussed from three aspects: active filtering, passive filtering, and hybrid filtering, and their respective mechanisms and engineering applicability are expounded. Finally, future trends are discussed, including the development of intelligent harmonic analysis and the transition of harmonic mitigation toward source suppression and coordinated governance. Recommendations such as lifecycle management and improvement of standards are also proposed.