An object detection method and apparatus for a vehicle in a confined space are provided. An object detection method for a vehicle traveling in a confined space, includes determining a first beam pattern and a second beam pattern based on geometric information of the confined space, detecting first candidate objects based on a first transmission signal emitted to form the first beam pattern using at least one antenna, detecting second candidate objects based on a second transmission signal emitted to form the second beam pattern using the at least one antenna, detecting at least one clutter object based on the first candidate objects and the second candidate objects, and detecting a target object based on the at least one clutter object.