At present

the closed clamp used to replace the single insulator of UHV transmission line is mainly made of titanium alloy material

which is heavy and inconvenient to use. Carbon fiber reinforced composites（CFRP）have the characteristics of low density and high strength

which can be used in lightweight design. However

the mechanical properties of CFRP are related to its ply structure

so it needs theoretical analysis. According to the structural and mechanical characteristics of the closed clamp

a 420 kN ceramic insulator closed clamp using carbon fiber composite material is designed in this paper. Five different fiber laying methods are considered. Based on the progressive damage theory of composite materials

the mechanical properties of five new clamps with different laying modes are calculated and analyzed by finite element method. The calculation results show that the failure location of the device will not be changed by the laying mode

but the ultimate bearing capacity of the device with the fifth laying mode is the largest. According to the above theoretical analysis

the self-weight of the new carbon fiber composite clamp is reduced by about 45%.