Objective:To investigate the clinical therapeutic effect and function mechanism of “Baogen-Ⅰ Decoction ” on Repeated Respiratory Tract Infection(RRTI)(deficiency of both lung and spleen, DBLP)  Methods:120 children with RRTI were assigned (DBLP) randomly into two groups, the test group treated with “Baogen-Ⅰ Decoction ” and the control group treated with Pidotimod Solution, and the course of the treatment was 8 weeks. The clinical efficacy and the cell group changes of T-cell subsets and immunoglobulin before and after treatment were observed  Results:The effective rate of test group and control group were 91.67% and 66.67% respectively. The clinical therapeutic effect of test group was better than that of control group(P,<,0.01). After the treatment, IgG, IgA and IgM level increased than that before the treatment in both groups(P,<,0.05,P,<,0.01). IgG, IgA and IgM level increased more significantly in test group than the control one(P,<,0.01) ; the level of CD3,+, CD4,+and, CD8,+, of the test group after the treatment increased than that before the treatment, and the level of CD3,+, and CD4,+, increased more significantly in test group than the control group (P,<,0.01)  Conclusion:“Baogen-Ⅰ Decoction” could well regulate the humoral immunity and cellular immunity of children with RRTI and has a better clinical efficacy in children RRTI (DBLP).