Compared with traditional onsite construction, prefabricated construction has a more complex working environment, resulting in more safety risks. While cognitive failure has been identified as a primary cause of intentional unsafe behaviors, there remains a lack of knowledge on the formation mechanism underlying intentional unsafe behaviors among workers in precast construction. Using the Theory of Planned Behavior and the risk preference variable, this study constructs a theoretical model for intentional unsafe behaviors of precast construction workers. Data related to precast construction and safety management activities is collected from 208 frontline workers. Structural Equation Modeling is used to test and modify the theoretical model in order to identify the formation mechanism and pathway underlying intentional unsafe behaviors. The findings show that: (1) workers' perceptual behavior control, behavior and attitude, risk preference, and subjective norms influence their intention to engage in unsafe behavior and subsequently lead to intentional unsafe behavior; (2) the effect of personal risk preference on intentional unsafe behaviors is significant, contributing 7.71% to overall intentional unsafe behavior; and (3) the effects of the observed variables are more evident than the initial theoretical model. The most prominent of these are the effects of task intensity (IBC1), safety equipment (IBC2), worker behavior (IOW1), historical behavior (IBC3), and behavioral belief (BAA3). Finally, comprehensive measures to control the intentional unsafe behaviors of precast construction workers are recommended. The results of this study are useful for reducing the occurrence of intentional unsafe behaviors by workers and reducing the incidence of accidents in a complex manufacturing-oriented construction environment.