Due to the tremendous economic value of search result pages, search engine companies have invested a lot to improve their quality. Recently, much effort has been made to directly model key aspects of users' interactions with search system, for example, Benefit and Cost. Time has been widely adopted in both of the two aspects since benefit and cost must be expressed in meaningful units in practical application. Psychological studies have demonstrated that the subjectively perceived time might be different from the objective time measured by timing device and the time perception process of human beings is a effcted by some psychological factors, such as motivation and interest, which are closely related to the search process. Considering that time is usually used to describe the subject experience of search users, it is necessary to investigate the di fference between perceived time and objective time in search process. In psychology, there is a temporal illusion effect named Vierordt's law, i.e. shorter intervals tend to be overestimated while longer intervals tend to be underestimated. In this work, we carefully designed a lab-study to examine the impact of duration length on user's time perception in the context of search. Experimental results show that Vierordt's law is consistently observed in Web search environment. This work could help us to correct the estimation of users' perceived time and provide insights about the mechanism of satisfaction.