This paper introduces a design of the cognitive information display using EID (Ecological Interface Design) for the water level control of steam generator in Korean advance nuclear power reactor. The concept of conventional display method in NPPs (Nuclear Power Plants) mainly relies on the SSSI (Single Sensor Single Indicator) design criteria; therefore, the conventional information display method employed a method based on the type of P&ID (Piping & Instrumentation Diagram). Due to the lack or excess of the information, the operators in NPPs could not understand the overall relationship between the objective and operator’s control; it leads to be a human’s cognitive decision burden and human error. In this paper, we propose the design method that applies the EID to the water level control of steam generator in advanced nuclear power reactor. This design method consists of the cognitive task analysis, the selection of the example task, the design of the example task, the feasibility evaluation. Proposed design method shows the effectiveness when developing the cognitive information display in NPPs. Also, this paper shows the further study points not only for applying the EID to real NPPs, but also for applying the EID to ubiquitous maintenance applications in real NPPs to overcome the lack of the information due to small screen.