The invention relates to the field of generation of engineering drawings of CATIA three-dimension design, and discloses a generation method of CATIA engineering drawing based on complicated background viewing and a system thereof. The method comprises the following steps: choosing a projection object from the original overall model together with a background object which is related to the projection object, and then copying and establishing a background model; recording information resources of the background object under the background model as well as the projection object information to XML configuration files. Through the XML configuration files, the positional relationship between the background object and the projection object under the background model can be renewed, thus the positional relation between the background object and the projection object under the background model can be updated in accord with the position under the original overall model. A project view is simultaneously jointly generated by the background model and the projection object. The generation method of CATIA engineering drawing based on complicated background viewing and the system thereof realize that the background model can be chosen across different categories according to different requirements in the CATIA three-dimension design, bringing more convenience in adjusting the background model, simplifying the size of the background model and improving the generation efficiency of a two-dimensional diagram.