On the condition of weak acid and over 95℃, wool fabrics were dyed with three tetrone dyes, which were synthesized by 2 – hydroxyl - 1,4 - naphthoquinone. Dry and wet rubbing fastnesses of dyed wool fabrics were mostly above 4 ~ 5, except for poor discolor fastness to soap and light, the wool and cotton staining fastness were both above 4. The maximum ultraviolet protection factor(UPF) of dyed wool fabric was 174, and the minimum of TUVA and TUVB were respectively 1.41% and 0.38%. Confirmed by fluorescence spectra, the three tetrone dyes have abilities of absorbing 290 ~ 400 nm UV light and translating it into the fluorescence. It was concluded that synthetic dyes enable dyed wool fabrics with outstanding UV protection properties.