By expounding the role of psychology in design, combined with real life cases, this paper proves that psychology plays a significant role in design. Design is to serve people. If we grasp the design psychology and analyze people's motivation psychology, we can meet people's needs with the greatest accuracy. Achieve the effect of designing and serving people. Through the guidance of design psychology, design meets people's psychological needs and conforms to design ethics, and then guides people's behaviors that are not easy to explore and pay attention to in their daily life. Design should be insightful and sensitive to the things around you. In this way, we can make a good design.