“Only ‘to have enough’ can be ‘to be more’” is a principle of Denis Goulet’s development ethics, which includes the following four problems: Why do people want to have more things? Is it better to have more things? What results do both relative superfluity and absolute misery of things make people? What system should we construct in order to deal with these problems? Accordingly, methods about the theoretic analysis and fact description are used to dram the following four conclusions: to have things is the hypothesis and basis of existence; “to have enough” has a proper limitation, that is, to have things which people must need, otherwise, we cannot “be” or “better be”; Both relative superfluity and absolute misery of things are inhuman,which do harm to the improvement of our true life quality. It is very important to build a system about a priority need theory.