The color matching and levelness of cotton fabrics dyed with reactive dye, in a non-aqueous environmentally-friendly medium of decamethylcyclopentasiloxane (D5), was investigated using the non-ionic surfactant reverse-micellar approach comprised of poly(ethylene glycol)-based surfactant. The calibration dyeing databases for both conventional water-based dyeing and D5-assisted reverse micellar dyeing were established, along with the dyeing of standard samples with predetermined concentrations. Computer color matching (CCM) was conducted by using different color difference formulae for both dyeing methods. Experimental results reveal that the measured concentrations were nearly the same as the expected concentrations for both methods. This indicates that the D5-assisted non-ionic reverse micellar dyeing approach can achieve color matching as good as the conventional dyeing system. The levelness of the dyed samples was measured according to the relative unlevelness indices (RUI), and the results reveal that the samples dyed by the D5 reverse micellar dyeing system can achieve good to excellent levelness comparable to that of the conventional dyeing system.