An improved trailer theft-thwarting coupling dock to prevent unauthorized coupling and hauling of the trailer coupling dock includes a coupling dock body, a upper mechanism, a lower mechanism and a lock assembly. The upper mechanism has a upper handle fastening to the lock assembly. Through locking and unlocking of the lock assembly, unauthorized opening of the upper mechanism can be prevented. Thereby the trailer coupling dock cannot be coupled and hauled unless authorized, and an improved theft-thwarting effect can be achieved for the trailer.