Abstract: This paper studied the changes under UV radiation of physiological and biochemical indexes in the N. tazetta Linn.var.chinensis stems and leaves, and provided a theoretical basis for the further development and utilization of island plants. In this experiment, the time of UV irradiation set up on the 3 gradient, 2, 12, 24h, 0h as control group. We were measured the SOD, POD, MDA, proline, electric conductivity, soluble protein, soluble sugar and chlorophyll other physiological and biochemical indexes of N. tazetta Linn.var.chinensis stems and leaves. The results showed that: with the time of UV-B expanding, the activity of SOD and POD in both stems and leaves were rise at first, and then drop, when the time up to 2 h, it the activity reached the highest. The activity of POD in stems is lower than leaves significantly. The proline, soluble sugar, MDA concentration and conductivity of Stems and leaves increased with prolonged UV radiation time. The contents of soluble protein in both leaves and stems were rise at first and then drop, the highest when the effect time for 12 h. Chlorophyll a, chlorophyll b and carotenoid were rise at first, and then rise, when the time up to 2 h, the contents of Chlorophyll a reached the highest. A comprehensive study that, under the ultraviolet radiation in 2~12h between, N. tazetta Linn.var.chinensis stems and leaves had stronger anti UV radiation characteristic, It could effectively relieve the ultraviolet radiation on the damage by itself.