Abstract： Objective： To observe the effect of the therapy of wet compress of Radix et Rhizoma Rhei and mirabilite combined with cluster nursing on preventing phlebitis in fracture patients during mannitol use. Methods： A total of 300 fracture patients treated with intravenous infusion of 20% mannitol were selected and divided into the control group and the observation group according to the random number table method，150 cases in each group. Both groups were treated with cluster nursing care， and the observation group was additionally treated with wet compress of Radix et Rhizoma Rhei and mirabilite. The incidence of phlebitis，the duration of needle retaining，and the pain，redness and swelling of needling orifice were compared between the two groups. Results：The severity of phlebitis in the observation group was lighter than that in the control group，the difference being significant(P＜0.05). The incidence of phlebitis was respectively 12.67% and 37.33% in the observation group and the control group， the difference being significant(P＜0.05). The proportion of the duration of needle retaining for less than two days in the observation group was 24.67%，lower than that of 39.33% in the control group (P＜0.05). The proportion of the duration of needle retaining more than five days in the observation group was 30.00%，higher than that of 18.67% in the control group(P＜0.05). After intervention，the pain score and the diameter of redness and swelling at the needling orifice in the two groups were improved；the above indexes in the observation group were improved better than those in the control group(P＜0.05). Conclusion：The therapy of wet compress of Radix et Rhizoma Rhei and mirabilite combined with cluster nursing can reduce the incidence of phlebitis in fracture patients during mannitol use， prolong the duration of needle retaining，relieve the pain and swelling of needling orifice.