Research conclusions:(1)The pre一condition of analyzing the use patterns of the existing route is to determine its functional orientation in the railway network. (2)There are mainly three ways for urban一suburban railway to utilize an existing railway line，including demolition and reconstruction，building a second line and building a new double一track line.(3)In the section of the shared route with existing line，it is quite necessary to analyze the current situation of the city and urban planning both at recent and in the long term. ( 4)The research results can provide references for other cities in cases of determining which way to choose when sharing route with the existing railway line.