The invention discloses a digital fabrics density 
detector and a testing method, the device includes a 
host machine, a bracket with a perforation on the end face, which is equipped in front of the 
host machine, a fabrics amplifying component, a CCD photoelectric coupled device, an 
image conversion circuit as well as a display apparatus, the test method of the tester includes the following steps: first of all, tiling the fabrics on a flattening table-board; then, placing the digital fabrics density 
detector on fabrics, switching-on a lighting lamp in the optical 
system towards the fabrics; regulating brightness of lighting lamp and display screen till the fabrics image is clear; then, putting the edge line of the straight ruler parallel to the non-testing 
system yarns, selecting a scale line of a straight ruler in alignment with the 
reticle in the middle of the display screen and uses the 
reticle as the 
initial point, rotating a transversal transmission mechanism and moving the optical 
system, counting the number of yarns within prescribed measurement distance; finally, fetching five test regions on the fabrics randomly, repeating the test steps, figuring out the mean value of 
thread count.