Social psychology treats conspiracy theories as an ideological belief which is defined as people’s tendency to interpret major social and political events as powerful groups or individuals who secretly deliberately plan to achieve their intended purpose. Belief in conspiracy theories is not just about believing in a specific conspiracy theory, but a general belief in all kinds of conspiracy theories. The following two findings in previous studies are sufficient to prove this point: one is the strong correlation between beliefs about the conspiracy theories behind different events; the other is that people may simultaneously embrace contradictory conspiracy theories about the same event. These two findings also indicate that belief in conspiracy theories is an integral and coherent psychological structure, which can be included into the category of psychological research as an independent variable. The negative influence of conspiracy theories is greater than the positive influence has become the consensus of researchers. To make a reasonable intervention in belief in conspiracy theories, we must first clarify the mechanism it generates. Previous studies have attempted to explain why people choose to believe in conspiracy theories from different perspectives. The results of studies on the relationship between belief in conspiracy theories and the Big Five personality are often difficult to replicate, so it seems that belief in conspiracy theories cannot be simply described by the Big Five personality dimensions. From the perspective of motivation, cognitive motives of reducing cognitive uncertainty and understanding the external world, existential motives of avoiding external threats and enhancing the sense of control and security, social motives of maintaining the positive image of competence and morality of individuals and inner groups can induce individuals to generate belief in conspiracy theories. Compared with other research perspectives, the perspective of social cognition seems to better reflect the internal psychological process of forming an ideological belief. This paper mainly introduces three explanations for the emergence of individual’s belief in conspiracy theories from the perspective of social cognition. Illusory pattern perception leads to people's cognitive tendency to establish connections between unrelated events and even impose causal relationships to generate belief in conspiracy theories. Hypersensitive agency detection affects people to look for the agency in the environment, and even over-perceive and assume the agency, purpose and intention behind the event, thus generating belief in conspiracy theories. Projection s people to infer the thoughts and behaviors of others in the event based on their own understanding and knowledge, and project their self-perception of "I am willing to participate in this event" onto others, thus promoting the belief in conspiracy theories that "others really plotted this event”. Although these three factors have corresponding theoretical and empirical support and have certain explanatory power for the generation of belief in conspiracy theories, it is difficult to explain that any of them are independent of other psychological mechanisms and independently generate belief in conspiracy theories. In the future study, it is suggested to combine social cognition, motivation, personality and other research perspectives, attach importance to experimental design and vertical research, expand the group of subjects, broaden measurement methods, and carry out cross-perspective, interdisciplinary and cross-cultural in-depth and systematic research on the generation mechanism of belief in conspiracy theories.