Continuous promotion and sustainable development of ultra-high voltage(UHV) transmission engineering construction in China has brought significant attention to the UHV post composite insulator owing to its unique advantages. However, the core diameter of ±800kV post composite insulator used in UHV engineering is almost larger than φ280mm.From the aspects of structural design, component preparation and performance test, the research of 'large-diameter' is highly significant. In terms of structural design, the researchers mainly use the mechanical load theory calculation or finite element simulation to explore the key nodes and the overall stress of the post composite insulator, and put forward the theory of optimizing the section design and the fixture fixing method, which lays the foundation for the structural design, improvement and optimization of large-diameter post composite insulator. The research on component preparation could be divided into two aspects : material formulation and molding process. For 'large-diameter' core cracking, insulation degradation and other issues, many studies have been carried out on toughening modification of epoxy resin, hydrophobic migration and recovery ability of sheds materials (high temperature vulcanized silicone rubber, hydrophobic aliphatic epoxy resin (HCEP)), optimization of curing conditions, and improvement of interfacial strength. However, there is still progressive space. The long-term operation reliability of toughened large-diameter core has not been studied yet. Moreover, the application of HCEP has not yet formed a general formula system. In terms of performance testing, have been done and obtained engineering conclusions research on the mechanical and electrical properties, seismic performance and aging characteristics of large-diameter post composite insulators. With the development of UHV transmission projects, the Chinese national standards have been gradually improved, while the post composite insulator materials still need to be continuously studied. In this work, the development trend of UHV large-diameter post composite insulators research were prospected. The summary of these research results would provide reference for the development of UHV large-diameter post composite insulators in the future.