The invention discloses a method and a device for establishing a boiler combustion process model, belonging to the technical field of energy power; the method comprises the following steps of extracting N groups of sample data from boiler combustion history sample data according to a characteristic of a boiler combustion process; by taking each group of the sample data as an input variable of each first genetic programming GP algorithm respectively and taking boiler efficiency and a nitric oxide NOx discharge value as an output variable of each first genetic programming GP algorithm respectively, respectively operating each first genetic programming GP algorithm through each cloud server group to obtain N groups of characteristic models; by taking the N groups of sample data as the input variable of a preset second genetic programming GP algorithm and taking the N groups of characteristic groups as an individual in an initial population of the second genetic programming GP algorithm, operating the second genetic programming GP algorithm to obtain the boiler combustion process model; according to the invention, the boiler combustion process model capable of reflecting the combustion process precisely can be established.