The purpose of this study was to investigate the changes of pain degrees and musculoarticulation functions in 8 baseball pitchers with shoulder joint injuries after the 12 week rehabilitative exercise therapy. 1. Before the rehabilitative exercise therapy, the pain degrees felt at the shoulder involved side were 2.87(±0.64), which showed between `severe` and `fair`. But it decreased after the 12 week rehabilitative exercise therapy. According to the pain scale, the 2nd(14.63%), 4th(29.26%), 6th(29.96%), 8th(60.97%), 10th(64.45%) and 12th(65.16%)weeks were decreased. However, only the 8th(60.97%), 10th(64.45%) and 12th(65.16%)weeks were statistically significant decreased and the pain degree in last 12th week was presented `no or mild pain`. 2. Before the rehabilitative exercise therapy, the musculoarticulation functions of the shoulder involved side was very decreased than the uninvolved side. But most of these variables were increased after the rehabilitative exercise therapy. The PT and PTBW of involved side abductor at 60d/sec were significantly increased 31.49%, 28.57% respectively. The PT and PTBW of involved side adductor at 60d/sec were significantly increased 38.65%, 36.14%. The PT and PTBW of involved side abductor at 180d/sec were significantly increased 26.75%, 24.33% respectively. And the acceleration time was significantly decreased 25%. The PT and PTBW of involved side adductor at 180d/sec were significantly increased 37.09%, 34.15% respectively. And the acceleration time was significantly decreased 28.57%. The PTBW of involved side abductor at 300d/sec was significantly increased 55.88%. The PT and PTBW of involved side adductor at 300d/sec were significantly increased 38.95%, 36.33% respectively. And the acceleration time was significantly decreased 41.66%. In conclusion, the rehabilitative exercise therapy performing during 12 weeks in this study was affected positive changes of pain degrees and muscular function in injured baseball pitchers. Therefore we think that the rehabilitative exercise therapy of this study seems to be available method for baseball pitchers with shoulder joint injuries.