There always has been a focus on helping operators deal with the situations in which they find themselves in the 50 years of human factors research. An important construct that continues this tradition is situation awareness (SA). Working memory and long-term memory seems at first blush to be a critical component of SA. Typically, in the human-machine system of visual monitoring, operator has several tasks at hand, some of which are in interrupted state while others are being carried out. There is evidence that some individuals develop better SA than others. The differences among individuals are attributed to the difference in the underlying cognitive processes that constitute SA. This study aims to reveal the memory process involved in the maintenance of SA in simulating visual monitoring task and disclose the relationship between memory process and SA difference among subjects. There are two alternative accounts both used to explain memory process in interrupted activities. The first is long-term working memory theory (LTWM). The second is template theory (TT). This study tested those ideas by creating very demanding interruption conditions that would hamper maintenance of pointer and other representations in short-term working memory over the interruption. A task of conflict detection with cockpit display of traffic information was simulated. Two experiments were performed to investigate the effect of interruption on situation awareness in conflict detection task. The independent variables of the two experiments were complexity of interruption task and subject experience (skilled subjects and novice subjects). The dependent variable is situation awareness. In experiment 1, the interruption task of mental rotation was adopted. In experiment 2, the interruption task of multiplication verification was adopted. The results of the two experiments showed that the interruption tasks had no effect on situation awareness of skilled subjects, regardless of the complexity of interruption tasks. Meanwhile, the situation awareness of novice subject deteriorated when the conflict task was interrupted by mental rotation task and multiplication verification task. The situation awareness of skilled subject was higher than novice subjects under each experimental treatment.