Abstract: The uniaxial tension creep tests for PVC coated fabric membrane material of 2/2 plain weave were executed on the warp and weft direction, while plastic deformation of the specimen were measured after 1 year. Using multiple functions from the product of both the stress difference power function and the time power function, the experiment data was studied on a multiple regression analysis. It was concluded that the model had better fitting results. At the same time, an instantaneous plastic and a transient plastic terms of the total plastic deformation were analyzed. It was showed that the instantaneous deformation was the main part of the plastic deformation, that the transient plastic terms was a minor part of the plastic deformation and the transient plastic terms would become smaller and smaller with time extension.