The LD pumped Nd∶YAG laser texturing equipment exhibiting a short pulse is established to explore the evolution process of the crater pit morphology generated by laser texturing. The effects of the process parameters, including the single pulse energy, pulse width, number of pulses, and defocusing amount, are investigated using the single factor method. Further, the evolution law of the texturing pit morphology on the 3A21 aluminum alloy sample surface is analyzed using an almost flat-top laser beam. The results denote that the pit morphology changes from an inverted trapezoid to an inverted triangle with the increasing single pulse energy. The competing metal slag and meteorite crater are formed around the pit as the pulse width narrows; further, the pit morphology and its characteristic parameters are observed to become stable under the action of sufficient pulses, and the micro-protrusion gradually decreases until it vanishes with an increase in the defocusing amount. These results establish a solid technological foundation for the 3A21 aluminum alloy with high-quality and morphology-controllable laser texturing.