In order to investigate the tensile properties of the plain rib knitted fabric, a three-dimensional model of the limited stretch was established. For the tensile properties of the plain rib knitted fabrics, the yarn diameter, the yarn elongation, the frictional coeffcient of the yarn, and the course and wale spacings were taken as the parameters. An equation that could represent the effect of these parameters on the tensile properties was formulated by using them.