An adaptable lock mounting device featuring adaptability and flexibility of use is configured to couple with a vehicle frame and includes a mounting base to detachably couple with a coupling base or an assembly base as appropriate, wherein the coupling base is different from the assembly base. A portion of the mounting base is one of a sliding block and a corresponding sliding sleeve to be fitted around the sliding block, while each of a portion of the coupling base and a portion of the assembly base is the other of the sliding block and the corresponding sliding sleeve.