ODA (Official Development Assistance) refers to the assistance provided by developed countries to developing countries or multilateral institutions to improve their economic development level and welfare level. It is a typical model of economic diplomacy after World War II and has become an important part of bilateral diplomacy. It is also widely concerned in multilateral diplomacy, but its operation often overflows the economic level and has the meaning of political diplomacy.

The theoretical basis of ODA: 1, the theory of national interests. The theory of national interests is the most common theoretical basis of foreign aid in developed countries, and is usually used to explain the self-interest of donor countries in bilateral aid. In the theoretical system of national interests, realists believe that foreign aid is a tool to protect or promote national security and sovereignty and resist hostile forces in the international environment. No matter what kind of foreign aid is political in nature, its main goal is to promote and protect national interests. Besides, there is no higher moral principle under the banner of foreign aid.

2. Supranational theory. European Community's foreign aid is an important example of supranational theory. In order to coordinate and integrate the EC member countries with different interests, the EC put forward the "3C" principles of foreign aid, namely, coordination, complementarity and consistency. These principles require the European Community and its member States to transcend national boundaries, avoid internal competition, give full play to their respective comparative advantages and complementarities, and integrate foreign development assistance policies and other policies in systems and ways in order to improve the efficiency of development assistance through concerted action.

After the project supported by foreign development aid agencies is completed, it is generally necessary to conduct post-evaluation of the project. The main purpose of post-evaluation is to sum up the experience and lessons in all aspects of project selection and implementation, evaluate the aid effect of loans and the role of development aid institutions, improve the transparency and credibility of development aid operations, and expand external influence through the disclosure of post-evaluation reports. According to the aid research report made by the Swedish International Development Agency and the United Nations Development Programme in 1996, the common problem encountered by aid agencies is that the achievements of aid mainly depend on the efforts of recipient countries.