Abstract: There are a large number of heat transfer fluid pipes in the heat collection field of the thermal storage parabolic trough solar thermal power generation project, and the thermal insulation materials and construction quantities are also large. The optimization of the thermal insulation layer thickness of the heat transfer fluid piping will improve the economy of the whole project. Taking the heat transfer fluid piping of a thermal storage parabolic trough solar thermal power generation project as an example, the thermal insulation thickness is optimized according to the cost of thermal insulation materials and the technical requirements of thermal insulation thickness, so as to achieve the economic optimization of the project. The optimization results can provide a basis for the design change of the thermal insulation layer of the heat transfer fluid piping of this project.