Adolescence is the critical period of individual development and is also the most sensitive period of depression. Suicides, especially the girls, rise significantly after puberty. By late adolescence, prevalence rate is increased to 4% a year. It is important practical significance for early treatment and intervention of adolescent depression, especially the prevention of adolescent suicide malignant events, to strengthen the neural mechanism research on adolescent depression. Major depression disorder is a disorder characterized by impaired emotion regulation．It is embodied as sustained negative affect and a persistent reduction in positive affect. Automatic emotion regulation ，driven by automatic goals, is a process in which people regulate their emotion without the control of consciousness. Automatic emotion regulation is common in our daily life, and is one of the key mechanisms of social and pathopsychological development of the individuals. Emotional dyregulation is the core characteristic of adolescent depression, and voluntary emotion regulation depends on automatic emotion regulation function, so the first place is to restore automatic emotion regulation function for the intervention of adolescent depression. Therefore, it is necessary to understand the neural mechanism of automatic emotion regulation in adolescent depression. Over the past few decades, neuroimaging studies have begun to suggest that ongoing structural and functional brain development during adolescence may contribute to adolescent-specific behaviors. They also show that structural development does not always occur linearly over time within brain areas, with quadratic and cubic trajectories often evident, nor does it occur uniformly across multiple brain regions. Depressed mood is probably the most easily recognized and familiar of the two key criteria for MDD. Anhedonia is less well-known than depressed mood in the general community, and is the second of the two key symptoms required for a diagnosis of MDD. At present, there are three theoretical models about depression in adolescence. The fractal triadic model is a neural systems approach developed to provide an understanding of the neural underpinnings of patterns of motivated behavior and of their changes across development or psychopathology. This model comprises three nodes that each presents a functional dominance over approach (striatum), avoidance (amygdala) and behavioral regulation (prefrontal cortex). The Social Information Processing Network (SIPN) offers a neural systems model similar in conception to the triadic model. It comprises three discrete nodes with specific, although overlapping, functions, that collaboratively integrate social information to influence behavior. Currently, the research mainly adopts automatic emotion regulation of implicit emotional paradigm. Experiments present emotional stimuli, but ones required subjects have nothing to do with the emotional cognitive tasks. By comparing the emotions and neutral condition, they can infer the relevant components of automatic emotion regulation. Neural model of emotion regulation indicates automatic emotion regulation depends on the ventral brain pathways, including the amygdala and insula, the ventral striatum, the ventromedial prefrontal cortex (VMPFC), the medial orbitofrontal cortex (mOFC), etc. This model is mainly based on animal and human brain imaging studies, for brain damage, clinical pathological study providing an important framework. With the development of neuroimaging techniques, functional connectivity, transcranial direct current stimulation (tDCS), and repetitive transcranial magnetic stimulation(rTMS), provide direct method for the prevention of the adolescent depression in the future.