A map constructing method adopted by a map constructing apparatus and includes steps of: continually obtaining colored image and depth-image information by an image sensor and a depth sensor of the map constructing apparatus while the map constructing apparatus is moving; recognizing the colored image for determining whether a dynamic object exists; labelling an object area corresponding to the location of the dynamic object if the dynamic object exists in the colored image; mapping the object area to a depth-image coordinate adopted by the depth-image information, searching for a corresponding position of the object area in the depth-image information and filtering the object area from the depth-image information for generating an adjusted depth-image information; and, inputting the adjusted depth-image information to a map constructing algorithm for establishing map data.