Based on qualitative analysis of information interchange relationship between management information systems of railway every main functional departments,the position and interaction of every management information systems has been specified by architecture grade analysis,and new method for railway information system integration to promote railway span development has been proposed,which should take transportation management information system as core because it has strong relationship and guide by security and financial accounting management information system.This new method catches the focal point and combines push and pull functions which will quick the development of railway informatization.