From the perspective of map cognition, this paper analyzes the important role of mental map in a successful event of family search. Firstly, several basic concepts of map cognition such as spatial cognition, mental map and cognition mapping are clarified, and the position and function of mental map in traditional cartographic triangle are expounded. A detailed empirical analysis is made on the cognitive process of both the seeker and the sought in this case. Three geospatial cognition problems in the interview are discussed: The adaptability difference of map tools to spatial cognition stage, the spatial scale and temporal characteristics of mental map matching, and the top-down influence of cognitive subjects'knowledge experience on cognitive results. Finally, this paper puts forward the development trend of geospatial cognition entering the new era under the promotion of brain science and artificial intelligence research.