To provide a plant operation support method and a program therefor, capable of successively and rapidly providing an optimum simulation model for a plant at a low cost.

This plant operation support method has a condition reception stage receiving input data used for simulation, target data to be a result of the simulation and decision conditions for deciding the quality of the simulation result, from a local system; a model preparing stage S26 preparing one or more simulation models from the input data and the target data; a model selection stage S27 deciding the quality of the results simulated by use of the prepared simulation models on the basis of the decision conditions and selecting the simulation model suitable for the conditions; and a delivery stage S33 delivering support information including the selected simulation model to the local system.