Objective To observe the efficacy and safety of the cocktail therapy to treat patients with Parkinson's disease with dementia ( PDD) . Methods Sixty patients with PDD were randomly divided into treatment group(30 cases)and control group(30 cases). The dose 10 mg of donepezil hydrochloride was taken 1 time a day in the control group;on the basis,the dose 0. 2 g of butylphthalide soft capsules was taken pre-dinner, 3 times a day,the dose 0. 8 g of oxiracetam was taken 3 times a day and 2 Ginkgo Biloba Leaves Extract tablets was taken 3 times a day in the treatment group,period of treatment was 6 months. The curative effect was measured by using Montreal cognitive assessment scale (MoCA),Blessed-Roth dementia table,severity of clinical dementia rating scale (WMS) rating, respectively before treatment and on the 3th, 6th month after treatment,and monitored the adverse reactions. Results There were no statistically significant differences on the scores of MoCA, WMS and Blessed-Roth dementia table between treatment group and control group before treatment ( all P>0. 05 ) . The scores of MoCA, WMS in the treatment group and control group on 6 months after treatment were significantly higher than those before treatment and 3 months after treatment, and the scores of Blessed-Roth dementia table in the treatment group and control group on 6 months after treatment were significantly lower than those before treatment and 3 months after treatment ( P<0. 05-0. 01). Compared with control group,the scores of MoCA, WMS increased obviously and the scores of Blessed-Roth dementia table decreased significantly in the treatment group on 6 months after treatment (P<0. 05-0. 01). There was no statistically significant difference on the rates of abnormal liver function after treatment betweenin the treatment group (16. 67%) and the control group (13. 33%) (P>0. 05). Conclusion The curative effect of cocktail therapy is better than traditional remedies for treating patients with PDD, and it is high safety.