Six aminoazobenzene disperse dyes derived from different N,N-dialkylanilines and 2-chloro-4-nitroaniline, were synthesized and their chemical structure were analyzed by 500 MHz NMR spectroscopy. The wavelength of maximum absorption of the synthesized dyes, which was dependent on the electron donating ability of the substituent, was in the range of 517.5~531.0 nm. As terminal alkyl group had more carbon, the dyeing rate of disperse dye decreased, the exhaustion rate became lower, and wash fastness of the dyed fabric improved. These results were discussed in terms of the molecular volume of the dispose dye and dye-fiber interaction such as van der Waals force.