A method for integrally forming a sole with hobnails includes the following steps: providing a mold assembly, the mold assembly includes a sole forming member and a hobnail forming member, the hobnail forming member is movable with respect to the sole forming member; forming of sole and hobnails, injecting plastic material into the mold cavity to integrally form the sole and a hobnail; demolding the hobnail, moving the hobnail forming member with respect to the sole forming member to create a buffer space between the hobnail and the hobnail forming member; and demolding of the sole, taking the sole with the hobnail obtained by the previous step out of the mold assembly, wherein an arc-shaped paw portion of the hobnail is bent through the buffer space and then demolded.