Abstract: When high-performance fibre fabrics and composites experience high-speed impact, the fibre materials near the impact point undergo transverse compression deformation, which affects the ballistic limit of the fabrics and composites. This paper presented a fibre-scale experimental device for transverse compression of materials, aiming to explore the deformation mechanism of fibre materials under transverse compression loads. This device reduced the impact of the surface roughness of the compression plates and eccentric loading during single-fibre compression through the dual-fibre compression method. It significantly reduced the systematic error of displacement measurement by optimizing the mounting method of the displacement sensor, increased the compression deformation range by reducing the size of the compression plates, and reduced the processing cost and time of the experimental device by optimizing the material of the compression plates. In this paper, the authors first introduced the composition of the experimental device and the experimental procedure. The system uncertainty was determined through non-sample loading experiments and error transitivity analysis, and then a thin-film compression experiment was designed to calibrate the system. Subsequently, experiments were carried out using poly(p-phenylene terephthalamide) fibre as an example to elaborate on the innovation of the experimental method. Morphological analysis of the loaded specimens using a scanning electron microscope (SEM) shows that the fibre material undergoes stable and uniform compression deformation, further verifying the rationality of the experimental method. Finally, based on the experimental test results, this paper introduces the nominal stress-strain curve of fibre transverse compression and approximate calculation methods for various mechanical property parameters. Research shows that compared with traditional dual-fibre compression testing systems, the characterization method proposed in this paper reduces the system uncertainty from 25.32% to 4.77%, and increase the maximum measurable compression strain from 60% to 75%. It improves the accuracy and range while saving manufacturing costs and accelerating the setup efficiency. This characterization method can provide experimental data for the micromechanical models of fabrics and composites, and has certain guiding significance for evaluating the mechanical properties of fibre materials and developing new high-performance fibre materials.