One of the most important characteristic features of a low-density thermally bonded non-woven material is its discontinuous and non-uniform microstructure, resulting in a complicated and unstable deformation mechanism of the material. In order to estimate the effects of such microstructure on the overall mechanical properties of the non-woven material, tensile tests are carried out for specimens with different systems of marks for both two principle directions-machine direction and cross direction-with images being captured with high-speed camera. The non-uniform strain fields are analysed based on the obtained images. Discontinuous finite-element models are developed to study the deformation mechanism of non-woven specimens in both principle directions, and the effects of the discontinuous and non-uniform fibrous network and different arrangements of bond points are analysed numerically.