The principle of legality constitutes one of the basic principles of the government’s rule of law, and as a result, it has been recognized as one of the most essential guarantees of human rights. The goals of sustainable development have a strong link with the principle of legality, and achievements in accomplishing a goal can frequently contribute to the accomplishment of other goals in addition. The United Arab Emirates’ constitutional framework, regulations, and rules, along with the goals for sustainable development (SDGs), were profoundly affected by the principle of legality. The method in which international standards and laws have been integrated into the UAE’s national legal framework provides definitive proof of this effect. The research concluded that all published and unofficial legal regulations have to be respected in order for public authorities to use within the limits of the principle of legality. These involve adhering to the standards of positive legitimacy and the fundamental regulations the community agrees on.

Tennis, as an important project of sports, has an obvious role in cultivating students' physical quality, observation ability and reaction speed. Under the background that the country attaches great importance to students' physical literacy, the traditional single and passive teaching has been unable to meet the practical needs, so it is necessary to strengthen the innovation of teaching methods. With the recognition of many teachers, the teaching method of "combining competition and practice" has been continuously promoted. The paper takes the combination of competition and practice as the teaching mode, and studies the teaching of college tennis sports.