This paper analyzes the causes of the unsafe behavior in construction workers and designs effective management measures. Through the identification, observation and investigation of the causes of construction workers' unsafe behavior, the cognitive reason is examined. In this paper, an event-related potential (ERP) measurement system consisting of a stimulus generation system (STIM), a signal acquisition and processing system, a subjects response system and a digital amplifier is constructed, and 15 people are tested as experimental subjects in the experimental research. The subjects are measured in the aspect of ERP signals before and after the psychological safety. The P3a components of the subjects are highest in the frontal area. In normal circumstances, P3a appears around 230ms, and the maximum amplitude appears around 270ms. Construction workers should subjectively create a healthy and stable psychological environment and control bad mood with rational minds.