Abstract: In order to achieve good fluorescent effect and wider chromatogram for dyed fluorescent acrylic yarn,trichromatic cationic dyes such as Fluorescent Yellow 10GFF,Brilliant Red X-5GN and Blue X-GRRL were used in combination dyeing of acrylic yarn with the optimal dyeing process.Meanwhile,one-bath process of whitening with fluorescent whitening agents and dyeing with cationic dyes was carried out on acrylic yarn.The experimental results show that more complete chromatogram of fluorescent acrylic yarn can be obtained with suitable proportion of mixed dyestuff in combination dyeing.TF-920,a fluorescent whitening agent,can further raise the fluorescence effect of acrylic yarn during one-bath process of whitening and dyeing.