The paper presents steady state model for the simulation of high pressure steam boiler. Models are developed for the various sections of the boiler, viz., furnace, superheater, boiler bank and air heater. A computer program is developed to solve these models. Simulation studies are carried out on an existing high pressure (45 kg(f)/cm(2)) steam boiler at different loads and the results are compared with the design and predicted values. The simulated results are in good agreement with the actual figures confirming the validity of the models to predict the performance of the boiler at different loads.