Laser forming of a micro-structural element involves a complex thermoplastic process. Numerous efforts had been made on the mechanisms of laser forming for macro-size elements, such as temperature gradient mechanism, buckling mechanism and upsetting mechanism, etc. It is found that the three mechanisms cannot depict fully the process of deformation in the macro-size element forming, let alone meet the needs of the micro-size one. Considering the laser inducing thermal stresses with size factors differing from the conventional analysis, it is essential to reveal the mechanisms dominating the forming process to accurately control the bending angle of a tiny plate. By studying the thermal transfer and elastic-plastic deformation of micro-structural element laser forming, the forming mechanism is explained within the micro size. The finite element model for laser bending is constructed for simulation. The stimulation results are agreement with the experimental data.