Objective To analyze the changes in the use of psychotropic drugs by inpatients in a psychiatric hospital in Guangzhou, and to provide reference for the control, rational application and scientific management of the drugs. Methods The sales amount, frequency of use, and daily use of psychotropic drugs from July 15, 2015 to July 14, 2019 were counted and analyzed. Results There were a total of 40 kinds of psychotropic drugs of 4 types in this hospital. In the past 4 years, the sales of antipsychotic drugs increased first and then decreased, and DDDs increased slightly. The sales amount of atypical antipsychotic drugs accounted for more than 97% of the total drug cost, and DDDs accounted for more than 87%. The sales amount of antidepressants DDDs were increasing year by year, and new generation antidepressants account for more than 99% of the antidepressants. The sales of anti-anxiety drugs increased first and then decreased. The sales of mood stabilizer increased first and then decreased, and DDDs decreased slightly. 65% of psychotropic drug's rank closes to 1. DDDc in 62% of the psychotropic drugs decreased; after abolishing additional cost of drugs, the total sales amount decreased, but the total DDDs increased. Conclusion Abolishing additional cost of drugs had a greater impact on antipsychotic drugs, but little effect for antidepressants, anxiolytics, and mood stabilizers, which may greatly reduces patient's drug cost and promote rational use of drugs.