The equivalent static load method (ESLM) provides an effective solution for dynamic response optimization technology,and is used in simple structures such as trusses,beams,rods,and thin plates that bear single mechanical load,or structures with lower grid requirements.But there are few researches under the coupled effect of heat-mechanical load.Therefore,the research of dynamic optimization method of heat-mechanical coupling structure based on ESLM has certain significance and value.Combining thermoelasticity with the equivalent static method,the equivalent static conversion mechanism of dynamic load under the coupling effect of thermal load and mechanical load was derived,and cantilever beam was taken as an example to verify the equivalent theory in thermophysical field and thermal-structure.The same applied to coupled physics.Taking a typical transient thermal-mechanical coupling structure:a diesel engine piston as the research object,the stress and displacement of the 16 key positions were extracted through the transient dynamics analysis of the piston-thermal-mechanical coupling,and the equivalent conversion calculation was carried out.The results show that the maximum equivalent stress error of the inspected area before and after equivalent transformation is within 3%,and the maximum displacement error is within 2%.Further analysis and comparison of the static optimization under the action of the piston thermomechanical load and the dynamic optimization based on ESLM show that the two optimized piston deformation,stress and temperature of the first ring groove are similar,but for the ESLM-based dynamic optimization,the piston mass is reduced by 4.7% compared to the static optimization.The research results fully prove the superiority of the ESLM-based dynamic optimization method.