The present disclosure relates to a graphene-nanoflower shaped MXene composite material, preparation method and application thereof, which belongs to the field of negative electrode materials for supercapacitors. In the present disclosure, a space-time shaping femtosecond laser is utilized to process MXene target in graphene oxide nanoflake dispersion, so as to synthesize a graphene-nanoflower shaped MXene composite material in one-step. This nanoflower shaped MXene has adjustable size and morphology and an extremely large specific surface area; when it is used in an electrode material for supercapacitors, the supercapacitor exhibits an extremely high specific capacitance and good cycle stability. This method utilizes a space-time shaping femtosecond laser to synthesize the graphene-nanoflower shaped MXene composite material, which is highly controllable, and can be used to uniformly prepare the material in large-scale. It has provided a new way for synthesis of materials.