The aim of this study was to investigate the effects of respiratory muscle training (RMT) with abdominal drawing-in maneuver (ADIM) on pulmonary function. Twenty-two subjects with restrictive breathing participated in this study. All the subjects were randomly assigned to three groups (7 subjects in RMT group, 7 subjects in RMT with ADIM group, 8 subjects in control group). The first group performed the RMT by using incentive respiratory spirometer (IRS). The second group performed the RMT by using IRS and the ADIM by using a Stabilizer. The exercises were conducted over four days. The pulmonary function was evaluated using the spirometer to measure the force exploratory volume in 1 second ($FEV_1$) and forced vital capacity (FVC). Measurements were conducted on the first day and the last day. A paired-t test was used for pre-post changes and the change rates in FVC and $FEV_1$ among each group were investigated by a one-way ANOVA. The findings of the the study were as follows: 1) There were significant differences of FVC and $FEV_1$ between pre and post in the two training groups (p<.05) 2) There was no significant difference of the change ratio the FVC and $FEV_1$ between the RMT group and RMT with ADIM group. Therefore, it is concluded that respiratory muscle and ADIM training, combined with two methods of treatment would suggest positive evidence for improving pulmonary function.