The project management develops from the World War II has exceeded until now for a half century, but due-date performance (DDP) still very low. In the past, the project management thought that DDP promote with difficulty, is because environment element of certainty influence. But Dr. Goldratt thought that is not the uncertainty factor affects DDP, instead is the problem which manages by the control variation production. In our paper, we verification this new viewpoint by a project experiment, and analyzes between the DDP and the uncertainty relations, as well as between the DDP and the management problem relations, Defining clearly the main factors affecting DDP in project.