An inspection apparatus and a method for segmenting an Image of a vehicle are disclosed. An X-ray transmission scanning is performed on the vehicle to obtain a transmission image. Each pixel of the transmission image is labeled with a category tag, by using a trained convolutional network. Images of respective parts of the vehicle are determined according to the category tag for each pixel. With the above solutions, it is possible to segment the images of respective parts of a vehicle more accurately in the situations that are complicated or have large variety kinds of vehicles.