Online teaching provides learners with more learning opportunities, but there are also many weaknesses that are not conducive to learning. Targeted instructional design can overcome the shortcomings of online learning and achieve better learning outcomes. In the teaching of legal courses at the China Open University Learning Center, blended teaching is guided by the principle of being closer to learners. Law course teachers strengthened the design of teaching activities in three aspects: In the construction of learning resources, content that is close to learners' lives is selected as much as possible to make learners feel familiar with the learning content; In the design of asynchronous learning activities, various strategies which actively guide teachers and facilitate learners' expression are adopted to increase learners' participation; In the design of real-time live teaching, digital tools are used to carry out interactive case teaching, which echoes asynchronous teaching activities and organically integrates dispersed learning activities, effectively improving the learning experience and enhancing learning effectiveness.