An analytical method is proposed to solute the steady characteristics of some special heat exchanging component.This paper discussed the double-faced heat transfer characteristic with helix inner tube,and puts up the energy equation of such heat exchanging component.After solving the equations with analytical method,an analytical expression is given,which can describe the liquid temperature distribution in the component.The method is used for solving two example.In the steam generator calculation,an iterative technique is used for calculating the length of apiece section.