On the one hand, based on the analysis of interdisciplinary research, this chapter aims to illustrate why people’s needs and behaviours matter, which will be the basis for creating the possible improved design process that can better integrate the consideration of people’s needs and their behaviours. On the other hand, this chapter uses a new-type conceptual model to understand human-centred design in a historical context, critically discussing what kind of people’s needs should eco-city meet, both physically and psychologically. It is new because this model reveals the design evolution, from functionality and usability to the higher-level desirability, which has responded to the hierarchy of human needs. Also, it has responded to one of viewpoints of this study, psychological needs matter in design process.