The invention discloses a method for boiler combustion optimization with the combination of the irreversible thermodynamics. The method is characterized by comprising the following steps that (1) when combustion optimization adjustment is conducted on a boiler, each time of parameter adjustment serves as an original working condition, overall modeling is conducted on the researched boiler, numerical simulation is conducted on the working conditions on the basis of a CFX platform, the carbon contact in fly ash and the emission value of NOx in each working condition can be given according to a simulation result, and original data required by calculation of radiation entropy generation and convection entropy generation can be obtained; (2) radiation entropy generation, conversion entropy generation and flow-resistance entropy generation of a heat-receiving face are calculated; (3) overall entropy generation of the heat-receiving face, the boiler heat efficiency, the carbon contact in the fly ash and the emission value of NOx serve as objective functions, and a combustion model is optimized through a least square support vector machine. According to the method, the irreversible thermodynamics is combined with boiler combustion optimization, so that the boiler can be better guided for actual operation.