摘要： The generalized photo-thermoelastic problem of a thick beam subjected to heat flux and photothermal conditions is studied. A modified multi-phase-lag photo-thermo-elasticity theory has been presented. The photothermal equation is added to other coupling thermoelasticity equations and all have been exactly solved. The state-space technique as well as the photothermal and mechanical conditions at the bounded faces of the beam is used for this purpose. The effect of multi-phase-lag and length-to-thickness ratio on the field quantities against the axial and normal directions of the beam under photothermal impacts is discussed. A validation example is considered to show the accuracy and efficiency of the current multi-phase-lag theory. Final investigations to the field quantities due to various photo-thermo-elastic models are made.