Forward Head Posture (FHP) is owing to abnormal position of head and neck, repeating work, chronic deficiency of exercise. Because of those are bring about muscle imbalance, tightness of cervical extensor muscle, weakness of cervical deep flexor muscle, instability of cervical region and headache. The purpose of the study was to evaluate the effect of sling exercise on muscle tension and pain of the neck in subjects with forward head posture. A total of 14 students with Forward Head Posture were measured by SPC. RULA program for the cranial rotation angle (CRA), craniovertebral angle (CVA). We measured the following variables: static surface Electromyography (EMG), Algometer, CRA, CVA. The sling exercise of our study contained elements such as strengthening, stretching, and stabilizing exercise on cervical parts. Collected data were statistically analyzed by SPSS Ver. 10.0. After experiment for 4 weeks period, Results were as following: 1) There was not a meaningful result in pain (p>0.05). 2) There was a meaningful result in changes of CRA and CVA (p<0.05). 3) There was a meaningful changes in muscle tone of upper trapezius and frontalis using EMG (p<0.05). According to this result, we could find out there was a significant correlation between sling exercise and muscle tone, CRA, CVA in subjects with forward head posture.