Based on the von Mises yield criterion and the elastoplastic constitutive relation, a spatial axisymmetric finite element model is established for long pulsed laser irradiating 7A04 aluminium alloys, and the temperature field and the thermal stress field are calculated by the finite-element/finite-difference hybrid algorithm when the laser beam with a Gaussian intensity profile heating the aluminium alloy plate. It is found that the Mises stress on the target surface distributes mainly within a certain scope around the center. At a position far from the center, the Mises stress is very small which barely affects the target and the Mises equivalent stress is far less than the yield strength of the aluminum alloy target. The consistency between the simulation and experimental results confirms the validity of the model.