A calibration device includes a base, a support column coupled to the base and extending in a first direction, and a crossbar coupled to the support column. The crossbar includes a positioning base and a carrier. The positioning base is fixed to the support column. The carrier is coupled to the positioning base and rotatable about a second direction perpendicular to the first direction. The carrier includes a distance sensor and a calibration platform. The calibration platform mounts a depth camera. The carrier is configured to rotate about the second direction to rotate an optical axis of the depth camera in a first calibration plane defined by the first direction and a third direction. The third direction is perpendicular to the first direction and the second direction.