It analyzes the passengers emotion and emotional feature while they are taking the subway and use the emotional design theory to instruct the design of metro platform screen door. With "emotional economy era" as the background and doing research on present situation of domestic and foreign metro platform screen door，it demonstrated the necessity of the emotional design in metro platform screen door. In addition，according to the analysis of passengers emotions， it put forward the proposal for the emotional design in metro platform screen door by using the three hierarchy theory of emotional design. Emotional design in metro platform screen door can relieve anxiety，depression and other emotions effectively and enhance the ease of use of metro platform screen door. It can help passengers to get more pleasure and humanized experience by using the emotional design theory to instruct the design of metro platform screen door.