The primary purpose of this research is to explore the decision-making mode of irrational trading behavior of individual investors in the Chinese stock market. In order to answer this question, based on the literature review, this thesis assumes that investors' irrational trading behavior decision is affected by personality, emotional state, overconfidence factors, and investors' gender, age, education background, and investment experience. Based on the big five personality theory and planned behavior theory, this research develops a model to simulate investors' decision-making process and uses Structure Equation Model as a data analysis method to test the hypothesis. Then, based on prospect theory and emotion theory, this thesis selects the disposition effect and overtrading behavior as the typical irrational trading behavior in the Chinese stock market to research the decision-making model. The statistical, path, moderate and mediating effect analyses were conducted on various factors which affect investors' trading intention and behavior decision. The result is that investors' trading decision in the Chinese market is influenced by their trading intention, emotional state, and confidence level. Moreover, investment intention is related to an investor's personality characteristics and internal factors such as gender, age, education background, and investment experience. Among them, personality directly determines investor cognition. It constitutes the inner factors of the decision model, while other internal factors have a moderate effect on investment intention. In conclusion, this thesis enriches the research on decision-making, irrational transactions, and investor sentiment and provides enlightenment for business practice and government policy establishment.