The invention provides an automobile head-on collision longitudinal-girder structure and belongs to the technical field of automobiles and solves the problem that an existing longitudinal girder cannot generate stable bending deformation in case of a collision. The automobile head-on collision longitudinal-girder structure comprises a longitudinal-girder inside plate and a longitudinal-girder outside plate, the side face of the front part of the longitudinal-girder inside plate and the side face of the front part of the longitudinal-girder outside plate are connected with the longitudinal-girder inside plate with continuous concave and convex wavy structures, the wavy structure on a longitudinal girder body has at least one wave crest and at least one wave trough, and one wave crest of thewavy structure on the longitudinal body is arranged at the corner of the junction of the longitudinal girder body and a dash board support section. The longitudinal girder body can generate stable bending deformation from left to right, transmission paths of head-on collision load are changed, the head-on collision load is ensured not to be axially transmitted to a dash board directly, energy from head-on collision is absorbed maximumly after bending deformation of the longitudinal girder body, less collision energy is transmitted to the dash board, and intrusion of the dash board is reduced.