In this paper the method of understanding of the complex object concept is presented. The proposed method of understanding the concept of the complex object is part of the shape understanding method developed by the authors. The main novelty of the presented method is that the process of understanding is related to the visual concept represented as a symbolic name of the possible class of shapes. The possible class of shapes, viewed as the hierarchical structures, is incorporated into the shape model. At each stage of the reasoning process that led to assigning of an examined object to one of the possible classes, the novel processing methods were used. These methods are very efficient because they dealt with a very specific class of shapes. These methods are implemented as a module of the shape understanding system and tested on the broad classes of shapes. The system of shape understanding is able to perform different tasks of shape analysis and recognition based on the ability of the system to understand the different concepts of shape at the different levels of cognition. The system consists of different types of experts that perform different processing and reasoning tasks.