Abstract: The principle of trait activation formalizes the trait–situation relationship by holding that the behavioral expression of a trait requires arousal of that trait by trait-relevant situational cues. Trait relevance and strength are distinct situational characteristics, and both are required for a full appreciation of situational factors involved in personality expression which have gradually gotten abroad attentions in the industrial and organizational psychology. This paper introduces the situational dimensions classification theory as well as the trait activation and evaluation model that are based upon the situational relevance. Traits will express as the work behaviour after the activation of some related cues in the situation. Consistent with the cues in the dimensions of different levels job behaviour may be evaluated as job performance. Several empirical researches have indicated that situational moderated variables may provide the trait aviation cues at three levels, and moderate the relationship between trait and work results, such as the job demand of task levels, the leadership behaviour of social levels, the leader-member exchange of the organizational levels and etc. The researcs on situation relevance play a important role in employee recruitmentc, performance mangement, production improvement and etc.

Key words: situation strength, situation relevance, situational dimensions classification theory, trail activation, situation moderator