Abstract: Carbon fibre reinforced composite (CFRC) materials have been widely adopted as replacement of metals for the construction of enclosures of platform targets, such as aircraft, ships, missiles, and so on. The shielding properties of CFRC materials play an important role in the electromagnetic safety of platform targets. There have been two difficulties in the calculation of shielding effectiveness of CFRC thin layer using the conventional full wave numerical methods:the complicated material properties of CFRC materials and the electrically large multi-scale problem due to the small thickness of CFRC thin layer. To overcome these two difficulties, homogeneous methods have been developed to obtain the equivalent homogeneous materials to the composite materials with complicated material properties and the embedded thin layer model techniques have been proposed to solve the electrically large multi-scale problems. In this paper, the high efficiently modelling techniques of CFRC thin layers will be discussed, from the perspective of homogenous method and embedded thin layer modelling techniques. Furthermore, the embedded thin layer technique integrated into the massively parallel full wave numerical software, JEMS-FDTD, will be briefly presented. In the end, the accuracy and high efficiency of JEMS-FDTD with the embedded thin layer modelling technique will be discussed using a numerical example. Besides, the shielding effectiveness of an aircraft with its skin made of CFRC materials will be calculated using JEMS-FDTD with the embedded thin layer technique, which indicates its applicability.