At present, the information transmission of human-computer interface relies more and more on the visual information in which the icon plays an important role as the carrier of information transmission. The design of radar interface icon will affect pilots' memory about interface information, which even cause the loss of situation awareness of pilots. However, in the current radar interface, weak semantic icons are used more frequently. Meanwhile, previous researches on icons do not consider the time pressure. Therefore, we want to explore the effect of icon semantic distance on working memory information extraction of radar interface under different time pressures. In this study, We designed two experiments to explore the above problems. Experiment 1 was conducted under no time pressure, we adopted 2 (icon semantic distance: weak semantic icon, strong semantic icon) × 5 (number of targets: 2,3,4,5,6) × 3 (target type: enemy aircraft, friendly aircraft, unidentified flying objects) within-subjects design. In experiment 1, subjects need to observe pictures to make corresponding responses, such as answering questions by pressing the key. Each picture presented 4 times, and each participant completed 120 trails in total. The eprime2.0 recorded the accuracy and reaction time of responses. In Experiment 2, in order to control the time pressure, the time for the participants to remember pictures was limited, which was half that of experiment 1. Other processes were the same as experiment 1.The number of participants was the same in the two experiments. After repeated measurement analysis of variance, the results showed that the response of strong semantic icon is faster than that of weak semantic icon only under time pressure[F(1,23)=6.90,p=.015,η2=.23]. The advantage of strong semantic icon under time pressure is also reflected in the accuracy of memory[F(1,23)=16.01,p=.001,η2=.41]. When the number of target is 3, the reaction is fastest and more accurate. At the same time, the response of enemy aircraft is longer than that of the friend aircraft and unidentified flying objects. According to the results of Experiment 1 and Experiment 2, we explored the role of time pressure which as the between subject variable. Repeated measurement analysis of variance was used to analyze the data of Experiment 1 and Experiment 2. We found that the interaction between icon semantic distance and time pressure is significant in the accuracy of question answer, but marginal significance in response time. In conclusion, working memory information extraction was used to explore the influence of icon semantic distance on radar interface information under different time pressures in this research. The results showed that strong semantic icon was easier to memory than weak semantic icon in radar interface under time pressure. Therefore, it is suggested that the icon design of radar interface should consider the icon semantic distance in the case of the same complexity and familiarity. At the same time, the interface information should not present too much content, which is better for pilots to recall the important information.