The present disclosure provides a laser drilling method and a laser drilling system. The laser drilling method includes a hole-boundary formation step of outputting a pulse laser beam and scanning a substrate to be drilled, to form a boundary cutting groove of a preformed hole; a material-in-hole heating step of outputting a CO2 laser beam, aligning the CO2 laser beam with the preformed hole, and heating a substrate material of the preformed hole for a predetermined period of time; and a hole formation step of cooling the substrate material of the preformed hole, to deform the substrate material and enable the substrate material to fall off from the substrate to be drilled.