Objective：To investigate the functional characteristics of the obitofrontal cortex in adolescent depressive patients by rest－ing-state functional magnetic resonance imaging（rs-fMRI）. Methods：A total of 71 adolescent depressive patients meeting DSM-IV diagnostic criteria were taken as case group，and 44 age-and sex-matched healthy adolescents as control group. Both group were scanned by 3.0T MRI scanner，and rs-fMRI data and T1-weighted images were obtained and processed with DPABI. Data were analyzed by amplitude of low-frequency fluctuation（ALFF） to obtain resting-state information between 0.01 to 0.1 Hz in orbital frontal cortex. Final results were subjected to permutation test and corrected by threshold-free cluster enhancement（TFCE）. Region of interest（ROI） was drawn for each subject based on the significantly changed brain area in ALFF. Functional connectivity（FC） was performed between ROI and bilateral thalamus and 12 limbic areas：bilateral amygdala，anterior-，middle- and posterior cingulate cortex，and hippocampus. Results：Compared with the healthy group，zALFF value of the left obitofrontal cortex reduced in the depression group（t=-2.23，P<0.05）. FC value showed that FC of the obitofrontal cortex and left thalamus decreased（P=0.024）. Conclusion：Compared with the healthy group，functional activities of the obitofrontal cortex show obvious abnormalities in patients with adolescent depression，which may be correlated with the pathophysiological mechanism of adolescent depression.