The aim of this research is reduction the symptoms of anxiety disorder, through MBCT. It seems that two main parameters of this treatment namely avoiding from mental rumination and avoidant states in a particular way with Anxiety Disorder. Meanwhile applying this type of treatment for reduction of the symptoms and rupture of disorder continuation chain could be useful. This is a Quasi-experimental research conducted on the basis of a pretest – posttest theory with a control group. The statistical society consists of the person with anxiety disorder referring to Sadr Psychiatry Hospital at Tehran. Among 300 files which were taken into consideration randomly, eighty persons were elected as anxiety by a psychiatrist, concerning input & output criteria. Beck anxiety questioner was used to evaluate Anxiety Symptoms. Twenty four persons were elected randomly and entered to the project. The elected persons were divided into two groups of test & control randomly, concerning same age and education. Data of the research were studied though covariance analysis method. Findings of the research indicated that applying mindfulness-Based Cognitive Therapy to persons with anxiety disorder reduces in symptoms hyper arousal, and negative behavior and cognition. However, it doesn't indicate reduction of avoidant symptom. Generally, reduction of anxiety in the test group in proportion with the control group was reported as significant. MBCT is effective on reducing in persons with anxiety disorder.