Objective To evaluate the clinical efficacy of trazodone in the treatment of sleep disorders (SD) in the senile dementia patients. Methods A total of 63 elderly dementia patients admitted in Changhai Hospital from January to December 2012, aged 60 to 80 (79.1±7.4) years, presenting SD, were randomly divided into trazodone group (n＝21), clonazepam group (n＝21) and amitriptyline group (n＝21). The course of therapy was 4 weeks for the 3 groups. The patients’ sleep status was assessed before and after treatment. The clinical efficacy was evaluated by Hamilton Anxiety Scale (HAMA) and Hamilton Depression Scale Rating (HAMD). The adverse effects were assessed by Treatment Emergent Symptom Scale (TESS). Results The total efficiency was 85.7% in trazodone group, significantly higher than that of amitriptyline group (76.2%) and clonazepam group (66.7%, Chi-sqaure＝6.860, P＜0.05). The HAMA and HAMD were dramatically lower in trazodone group than in clonazepam group (t＝4.21, 5.13; P＜0.05) and amitriptyline group(t＝6.47, 7.24; P＜0.05). The trazodone group had lower incidence of adverse reactions, milder side effects and better tolerance. Conclusion Trazodone can effectively relieve SD and accompanying anxiety and depression in the senile dementia patients only with mild side effect, which is worth to further clinical study.