Abstract: The combined operation of express/local trains can better adapt to the unbalanced spatial-temporal distribution of passenger flow on suburban lines. In order to study the mechanism of various factors influencing the passing capacity under express/local mode, considering the characteristics of express/local mode transport organization and the ideological essence of removal coefficient method, the removal coefficient value of each factor of the passing capacity in different conditions under express/local mode are quantitatively presented. A calculating method of suburban line passing capacity under express/local mode based on removal coefficient is proposed. Taking Shanghai Rail Transit Line 16 as an example, the passing capacity with factors including different quantities and locations of overtaking is calculated.