Purpose The purpose of this study was to determine the effects of forced inspiration and forced inspiration and forced expiration exercise on stroke patients’ trunk muscle activity, trunk control ability. Methods Twenty four patients with stroke were randomly assigned to a control group with physical therapy and a complex breath exercise as well. The complex breath exercise group received physical therapy for 30 minutes and complex breath exercise for 30 minutes and the control group received physical therapy 60 minutes. All of them conducted exercises 5 times per week for 6 weeks. Surface Electromyogram used to measure trunk muscle activity of paretic side. Trunk Impairment scale used to trunk control. Results The result of this study were as follows: Compare complex breath exercise group and control group showed a significantly difference in rectus abdominalis, external oblique, internal oblique (p<.001). Trunk control showed a significantly difference in complex breath exercise group (p<.001). Conclusion The result of this study suggest that complex breath exercise increase trunk muscle activity, trunk control and balance