Four kinds of spunbonded nonwoven fabrics having different fiber orientation were produced by changing the speed of net conveyor in the spunbonding process. Degree of fiber orientation was measured by using image analyzer. The influence of fiber orientation on the physical properties of spun bonded nonwoven fabrics was studied. The tensile properties such as tensile strength, initial modulus and yield stress are increased with the degree of fiber orientation, on the contrary, the tearing strength is decreased. The anisotropy of these tensile properties is increased with the degree of fiber orientation. Especially, the increse in anisotropy of the initial modulus and the yield stress, which is related to the small range deformation, is remarkable.