As the basic process and important way of social cognition, social categorization is the subjective process of dividing others into different groups based on shared similarity. It is also the focus of current researchers such as cognitive psychology and social psychology. Social categorization organizes the rich knowledge about human attributes and about the complex network of human social life, and it plays critical role to understand the self in the interpersonal group, give meaning and reduce uncertainty, predict stereotypes and intergroup perception, promote reasoning and decision-making and to guide the inference of social relations. In general, people are often based on various types of cues for social categorization, which can be summarized as obvious cues and ambiguous cues, natural/ physiological cues and social cues, and static cues and dynamic cues. Specifically, people usually classify others based on some relatively stable and immutable obvious cues such as face shape and skin color and the process is automatic and unconscious. In addition to obvious visual cues, some cues that are relatively vague (such as sexual orientation, religious belief) are also important basis for social categorization. Gender, race and age are called the “Big Three” category and are important natural cues for social categorization. In addition to natural cues, people also classify others according to social cues such as professional roles and status. Static cues such as resumes, archives and other text information also serve as an important basis for social categorization. In addition to static cues, dynamic cues including facial expression and voice tones in interpersonal interaction are also important references for social categorization. Social categorization will be affected by a series of social cognitional factors such as the objects classified, context and perceives. For example, the factors of objects such as the different types of categories (single or multidimensional), the accessibility and salience of categories, the factors of context such as the different cultural backgrounds, living conditions and cooperation and competitive context, and the factors of perceivers such as experience, motivations, intentions, collective memories and identity changes will have an impact on social categorization. Furthermore, in most situations, social categorization is a rapid, efficient and spontaneous process, so the underlying psychological mechanisms of social categorization are diverse and complex. In general, the need for structure and certainty and group identity are important mechanisms of social categorization. Moreover, social categorization is of profoundly implication to the perception, memory and information coding of interpersonal interaction. However, social categorization will produce a series of negative effects on people’s psychology and behavior. For example, cognitive bias such as stereotypes, emotion recognition, prejudice and behavior inferences will be influenced by social categorization. Finally, it will become the main direction of future research to explore the social categories preferences based on the cross-cultural and development perspectives, explore the potential mechanisms, and examine the influences of social categorization and the intervention strategies based on the local cultural research.