Objective. To observe the effect of 12-week core stability training on Cobb angle and the ratios of AEMG (averaged EMG) and IEMG (integral EMG) of paravertebral electromyography in thoracic and lumbar segments in adolescent idiopathic scoliosis (AIS) patients and offer a practical-based evidence for the rehabilitation treatment for AIS patients. Methods. 31 AIS female middle school students were randomly divided into an exercise group ( n = 16 , 12 weeks of core stability training, 3 times/week) and AIS group ( n = 15 ). In addition, 15 female secondary school students without scoliosis were included as the normal group (the AIS group and normal group did not perform any regular physical exercise throughout the trial period and only receive regular evaluation and guidance). Before and after the experiment, the digital diagnostic equipment of Philips was used to examine the Cobb angle and Noraxon was used to measure the surface EMG signals of the back thoracic and lumbar paravertebral muscles. Results. Compared with that before training, after 12 weeks of core stability training, the Cobb angle in the exercise group significantly decreased, and the ratio of AEMG (convex/concave) and IEMG (convex/concave) of paravertebral muscles in the thoracolumbar segment significantly decreased ( P < 0.01 , respectively); there was no significant difference in the above indicators in the AIS group before and after the experiment ( P > 0.05 , respectively). After 12 weeks of core stability training, compared with the AIS group, the Cobb angle decreased significantly ( P < 0.01 ), and the ratio of AEMG (convex/concave) and IEMG (convex/concave) of paravertebral muscles in thoracolumbar segment decreased significantly ( P < 0.01 , P < 0.05 ). Compared with the normal group, the ratio of AEMG and IEMG of paravertebral muscles in thoracolumbar segment significantly increased ( P < 0.01 ) in the AIS group ( P < 0.01 , respectively). Conclusions. The core stability training can significantly reduce the Cobb angle of AIS and correct the bad posture of scoliosis patients, which may be related to the balance of the electromyographic activities (convex concave side) of paravertebral muscles in AIS patients.