Abstract: Power grid operation state refers to the complete process of power generation, transmission, distribution and consumption. Visualization approaches used to analyze power gird operation state perform better than traditional methods by combining human knowledge into the data analysis process and therefore, are widely used for power grid operation state analysis. In this paper, we introduce the three most commonly used data types in power grid data visualization and the four visualization tasks. We survey and summarize the existing visualization works that are used to solve power grid problems. The advantages and disadvantages of these methods are explained from two perspectives: data and task. However, there still exist multiple challenges in this research domain, such as dealing with large-scale data and stream data as well as the lack of comprehensive analysis tools.