Eliminating workers’ unsafe behavior is one of the most important goals for onsite management and behavior-based safety programs have been widely used. However, the existing method lacks consideration of the worker’s inner and personal factors causing the decrease in the effectiveness of the measures. This study puts forward a personalization method for safety interventions and aims to examine the effectiveness and practicability of this change in safety interventions to reduce construction workers’ unsafe behaviors. Personalization of safety interventions was achieved through a diagnostic intervention model targeting the construction worker’s cognitive-based competence, psychological needs, and safety motivation with consideration of personality traits. The workers’ data were collected via a questionnaire and smart helmets on a building construction site. The results indicate that addressing these inner factors could achieve a persistent positive effect on construction workers’ safe behaviors. The effect size of improvement on cognitive-based competence is more than that of safety motivation. Improvements in long-term memory retrieval ability, subjective norms, and risk tolerance are the most significant in the cognitive-based competence. Personalized safety interventions and the current safety management are compatible.