Abstract: From the perspective of the control room development of nuclear power plants (NPPs), the first generation is the main analog technology on the control room, the second generation is the combination of analog and digital technologies, and the third generation is based on full digital technology. The digital human-machine interface (HMI) of the third generation control room can realize the functions which the first generation and second generation can not realize. But the large and concentrated information also may be beyond the information processing ability of the operator and reduces the efficiency of the operator to receive information, affecting the performance of the operator. Combined with the relevant law and regulation standards, this paper was based on the technology development trend of HMI and regarded the control room and HMI of LingAo Phase Ⅱ NPP as an example. The characteristics of the digital HMI of the third generation control room were summarized, and also the main problems and optimization measures were analyzed. As a result, it is also benefit to the design of control room HMI as the technical references.