The glass fiber fabrics treated with a coupling agent that contains aminoethyl groups are used as a dye with a procedure similar to that for nylon with acid dyestuff and after-chroming. Furthermore, we investigated the dyeing parameters and physical properties. Results revealed that the glass fiber fabrics treated with the coupling agent were dyeable. The best conditions for acid dyestuff are at pH = 6 and at 5% owf (on the weight of fiber) concentration of dyestuff; for after-chroming, they are at 1.4% owf concentration of potassium dichromate and at 70 degrees C for 50 min. In addition, the fabrics dyed have much better colorfastness (4-5 grade), and the average dyeing evenness is lower than 1.5.