An improved F.R.L. fabric drape test system has been established with computer image process method. Image data has been collected through the video camera, installed on the top of the system. Since all of the image data point can be traced, this system can analyse not only drape coefficient but also other factors characterizing the shape of drape wave and nodal points, which are aestheticically important for fabric performance. In this study several non-dimensional quantities have been defined to characterize drape waves. One of the non-dimensional quantity, J=Wl/B showed good correlation with fabric drape coefficient.