The features of urban rail transit network operation have multiplied the difficulties to passenger guidance under metro emergency conditions. For example, it's in a semi-closed space with high intensity and diverse types of passenger flow, who have different destinations. In particular, there are the elderly and children in the metro emergencies, more attention and help needed. In this article, the daily passenger flow distribution features are first studied for the analysis and prediction of the passenger distribution and propagation in emergencies. Then, the demand analyses on the passenger guidance system under emergency conditions are conducted. Moreover, the function modules are designed to meet the demand analysis and the functional structure of the system is detailedly analyzed and established. In the end, the implementation conception of the system is described.