Social interaction is the foundation of information communication, however, the underlying neural underpinnings of it is still an open question. The article aims to elaborate its behavioral and neural dynamics. Recently, many neuroscientists use a neuroimaging technique called ‘hyperscanning’ to investigate this issue. This technique is collecting data by simultaneously recording the hemodynamic or neuroelectric activities of multiple subjects. Many studies have discovered interpersonal neural synchronization (INS) in some specific brain regions during real-time interaction between or among human. Therefore, neuroscientists adopted INS as an index to investigate the mechanism of social interaction. According to some major findings and theoretical assumptions of social cognition in the field of neuroscience, neuroscientists put forward a dual mechanism neural framework for social understanding. They proposed that social understanding must be achieved via at least two mechanisms (Theory of Mind and Mirror Neuron System), which are capable of parallel information processing in the brain. The first mechanism (Mirror Neuron System) suggests that representations of others are mapped onto an observer’s representations of these same schemas in order to understand them, revealing the neural mechanisms of simple motor perception and imitation during social communication from a neurophysiological perspective. The second mechanism (Theory of Mind) requires semantic analysis of a given social situation to understand others and most likely involves conscious processes, revealing the neural mechanisms of inferring mental state of others during social communication from the theory perspective of social cognitive. Previous studies found some synchronized brain regions were partly coincident with the speculated brain areas of Theory of Mind and Mirror Neuron System, indicating that communication processes activated one or two mechanisms and caused controversy on cognitive mechanisms, which may be resulted from the form of communication (verbal or nonverbal communication). Therefore, from the aspects of verbal communication and nonverbal communication, we briefly summarized recent studies of INS during social interactions. However, due to the complexity of social interactions, INS during different task may active different brain areas that belong to Theory of Mind or Mirror Neuron System. This may be influenced by many communication factors, such as communicative purpose, objects, form or content. Specifically, INS was observed during implicit social interaction without communication purpose (communication purpose); INS of subjects with autistic spectrum disorder was reduced compared with normal subjects (communication object); INS during face-to-face communication was stronger than other modes of communication (communication form); INS was increased during cooperation task but not during competition (communication content). In short, the two mechanisms are both involved in social interaction or the understanding of others. It suggests that maybe researchers should put their eyes on what systems are activated, and in what way, rather than trying to find out which system is the only one that exists. And, future researches should pay more attention to the following aspects. First, whether these two mechanisms showed INS in different brain regions due to purpose, objects, form or content of communication. Second, how these two mechanisms worked together or separately in different tasks and situations. These can not only discover the cognitive mechanism of INS, but also provide a reference for the study of groups with cognitive deficit.