Objective To examine the impact of case management on hospitalizations of the chronically and severely mentally ill patients in Zhongshan. Methods Patients with severe and chronic mental illness,aged ≥ 15 years and living in pilot area were divided into two groups naturally since the program of case management launched, 65 cases in the group of case management and 112 patients in the group of standard management. Hospitalizations of the two groups before and after case management were compared. Results Data were analysised with MIXED procedure. Length of stay in days per admission (LOS) of both groups decreased with time in years (F=11.02, P=0.001), and the decline in LOS of case management group was greater than that of standard management group (F=9.02, P=0.003). The average admissions of case management group was more than that of standard management group (F=4.98,P=0.03). There was no significant differences in average hospitalization incidents before and after case management in both groups(case management group 5.13%vs. 5.38%, standard management group 7.14%vs. 8.92%, P>0.05). Conclusions Case management was effective in reducing hospitalizations for a group of Chinese with chronic and severe mental illness, and may contribute to the balance on mental health resources between community and hospital.