Ultraviolet radiation is a double-edged sword to life .
If it is too strong , the terrestrial biological systems will be damaged .
And if it is too weak , the synthesis of many biochemical compounds can not go along .
We try to obtain the continuous ultraviolet habitable zones , and compare the ultraviolet habitable zones with the habitable zones of host stars .
Using the boundary ultraviolet radiation of ultraviolet habitable zone , we calculate the ultraviolet habitable zones of host stars with masses from 0.08 to 4.00 M _ { \odot } .
For the host stars with effective temperatures lower than 4,600 K , the ultraviolet habitable zones are closer than the habitable zones .
For the host stars with effective temperatures higher than 7,137 K , the ultraviolet habitable zones are farther than the habitable zones .
For hot subdwarf as a host star , the distance of the ultraviolet habitable zone is about ten times more than that of the habitable zone , which is not suitable for life existence .