This paper aims to investigate the impact of complexity and mystery on the perceived legibility of citizens in urban parks. The theoretical framework is based on Rachel and Stephen Kaplan’s theory (four cognitive states) and Lynch’s legibility theory. The method is descriptive correlational. Data collection was done through a survey questionnaire and mental maps. The paper uses Lynch’s mental maps and asks people to draw some aspects of the parks they remembered the most and compare the results with the surveys. The data analysis uses descriptive and inferential techniques as well as logical reasoning. The research claims a significant correlation with a higher-than-average coefficient between the legibility indicators (path, edge, node, district, landmark) and complexity and mystery in urban parks. The conclusion is that districts in urban parks have the most significant impact on the overlapping of citizens’ collective mental maps. Landmarks, paths, edges, and entrances are almost equally and moderately fuzzy-scale on the legibility of citizens’ mental maps in urban parks. Nodes play less of a role in citizens’ collective mental maps than other park elements. Parks with too many entrances, non-linear paths, indistinguishable districts, and undefined edges are not perceptible to citizens, and citizens’ perceptions of space differ significantly from the existing reality. The correlation between legibility dimensions, such as edges, nodes, landmarks, districts, paths, and entrances, is higher than the fuzzy scale average. Moreover, the legibility in each dimension will affect legibility dimensions a lot. Lynch’s theory of legibility in the spatial perception of parks and Kaplan’s theory of complexity and mystery criteria appear to be not fully responsive. It differs based on the features of each park, such as openness and closeness. For future research, it is better to comprehensively understand by using all dimensions of Kalpan’s theory: complexity, mystery, refuge, and prospect.