Objective: This study proposes an alarm display and compares it with the one(alarm tile display) widely used in main control rooms(MCRs) of nuclear power plants. Background: Catching up with the rapid development of computer technologies, advanced MCRs has been required. Using modern technologies of computers and visual displays, we have a lot of potential to improve user performance and satisfaction as well as safety in MCRs. Method: The alarm bar display has been proposed to reduce some potential problems of the alarm tile display in this study. Human factors evaluations were conducted to compare both types of displays. Two interfaces of bar alarm and tile alarm were simulated on the desktop computer for the user-involved experiment. Eight students participated in the experiment with the within-subject design. Results: The alarm bar was slightly better in terms of situation awareness, and preferred to understand alarm dynamics. The alarm tile was slightly or significantly better in other measures. Conclusion: Both alarm displays have their own advantages and disadvantages. Therefore, combining benefits of both displays can be used to optimize the design of alarm displays. Application: The proposed display is expected to compensate the existing displays for certain purposes.