Computation of temperature field of turbine rotor is a two-dimension axisymmetric problem. A two-dimension computing model of rotor temperature field is obtained by the analysis and simplification of rotor geometry structure and boundary conditions. The finite difference method is used to compute two-dimension temperature field of turbine rotor in this paper, which has enough precision and low amount of computation for online monitoring. By simplifying the structure and boundary conditions of turbine rotor, the fifteen node types of rotor are obtained. The difference calculating formulas for all node types are given. According to the model and difference formulas, an online computing program of temperature field of turbine rotor has been developed and applied to a 200MW turbine. Color cloud picture of temperature field of turbine rotor is released online via Internet.Copyright © 2006 by ASME