The influence of the tensile force on deformation properties of two bar warp knitted fabrics during relaxation was investigated. For this purpose the sampels of locknit were manufactured and loaded with force equal to 50％ of tensile load. The relaxation course was analysed by using the Alfrey rheological model. The parameters of the rheological model were calculated with the computer programme. Simultaneously the elasticity of this kind of fabric as a function of different density was investigated. The course of relaxation of locknit was interpreted and the conclusion was made that the relaxation of locknit depends on the applied tensile force, which many not exceed 5％ of the tensile breaking load, otherwise it causes the permanent deformation of the fabric, especially in the weft direction.