Abstract: In order to open up the application field of ultrasonic technology in textile dyeing,an applied study of ultrasonic dyeing of the hemp fabric with vat dyes was carried out.The results show that compared with the conventional dyeing process,ultrasonic dyeing technology can improve the abrasion fastness of the dyed fabric significantly,enhance dye up-take with the amount of dyes lessened and environment-pollution reduced,increase the diffusion coefficient,thus reducing the activated energy of dyeing,saving energy and raising productivity. Ultrasonic technology makes it possible the low temperature dyeing of the hemp fabric with vat dyes in a shortened process.