Abstract: In order to improve the light fastness of polyester fabrics, 2-(2,4-dihydroxyphenyl)-4,6- bis(2,4-dimethylphenyl)-s-triazine (simply named as UV-Abs in this paper) with an o-hydroxyphenyl-s-triazine group in the molecule was prepared which has the performance of a UV-absorber. The UV-Abs was dyed onto polyester fabric with high temperature and high pressure processing. The effects of it on the improving of ultraviolet protection and the light fastness of polyester fabrics were discussed. The results showed, this o-hydroxyphenyl-s-triazine compound has a relative high uptake rate on polyester under high temperature and high pressure condition. On the polyester fabrics dyed either with UV-Abs alone or together with dyes, there were obvious improvement on ultraviolet protection. The yellowing of polyester fabrics dyed with UV-Abs alone declined. The dyeing of UV-Abs with disperse dyes in one bath could improve the light fastness of polyester fabrics in a certain extent.