The purpose of this study is to evaluate the impact of Acceptance and Commitment Therapy (ACT) compared with Cognitive Behavior Therapy (CBT) on quality of life in patients with chronic low back pain. For this purpose, according to chronic pain criteria and other inclusion criteria, such as having 18 to 50 years, do not using any treatment (other than medication) during the intervention period and willingness to participate in the study and finally, after diagnosis by pain specialist, 45 patients with chronic low back pain select by purposive sampling from patients referred to a pain clinic in Akhtar Hospital. Then, they are randomly (using lottery) assigned to the ACT (15 patients), CBT (15 patients) and control (15 patients) group. In acceptance and commitment therapy, in order to enhance quality of life in patient, focus on their psychological flexibility and commitment to the implementation of the value of their lives. The cognitive and behavioral therapy, in order to enhance the quality of life in patients, focus on the challenge with thoughts and exposure and in control group do not implement any intervention. Quality of Life Questionnaire conduct in the three groups at pretest and posttest, and finally, after the interventions, results of the groups compare with together.