Purpose In the case of spastic dysarthria patients, their posture because asymmetrical due to excessive muscle tension, and an unstable breathing pattern becomes visible for this reason. The purpose of this study measured and compared the effects of trunk realignment and Proprioceptive Neuromuscular Facilitation (PNF) on the maximum phonation time and intensity in phonation of spastic dysarthria patients. Methods Trunk realignment was based on Bobath treatment, using PNF for respiration exercises. Patients were manually treated considering inspiration and expiration. A laptop computer and a headset with a microphone were used to measure the change of maximum phonation time in order to determent for improvement in phonation, and the speech analysis program Praat (ver. 5329) was installed into the computer for evaluation to achieve a more objective data presentation. Each test subjects went through a total of 26 sessions which lasted 30 minutes for 5 days a week, the sessions were divided into the preliminary stage (3 sessions), the treatment stage (20 sessions), and the post treatment stage (3 sessions). The collected data compared and analyzed the change of phonation intensity and maximum phonation time through visual graphs and average value of the descriptive statistics. Results First, respiration exercise with trunk realignment and PNF was measured by Praat, a speech analysis program, and found out its effect on increasing the maximum phonation time in the patients with spastic dysarthria. Second, respiration exercise with trunk realignment and PNF was measured by Praat, a speech analysis program, and found out its effect on increasing the phonation intensity in the patients with spastic dysarthria. Conclusions This study affected on the spastic dysarthria patients to make them experience the normal respiratory patterns and speaking in proper positions by treating them with Bobath trunk realignment and PNF for a positive outcome.