Abstract：As the ageing society looming ,needs ,supports and the welling-being of the senior citizen becoming more and more important. The Primary purpose of this research was to determine the relationship between the needs, the social supports and mental health of urban low age senior citizen. The research surveys 738 urban low age senior citizen by the urban low age senior citizen need questionnaire, the urban low age senior citizen social support questionnaire and senior citizen mental health questionnaire. By using the LISREL8.7, the Structural Equation Model of the relationship between the needs, the social supports and mental health of urban low age senior citizen was established. The result shows that: Both the need and social support of old person affect the mental health of old person. To be specify, the satisfaction relationship need and the satisfaction of dear ones need partially mediate the affection support and mental health; the satisfaction of relationship need, satisfaction of dear ones need, the satisfaction of cognation need and the satisfaction of value need fully mediate the guidance support and mental health. In this study, we found the social supports and the needs of low age senior citizen affect their mental health. The social supports of low age senior citizen affect the their mental health from the connection of their needs.