with the promotion of quality education, the value of primary school art color teaching is prominent, but the current single class hour and fragmented teaching mode limits the development of students. Large unit teaching emphasizes the integrity and relevance of knowledge, which can solve this problem. This paper points out that the color teaching of primary school fine arts large unit is faced with realistic difficulties such as the fragmentation of teaching content, the fuzziness of teaching objectives, the simplification of situation, the shallowness of practice, and the simplification of evaluation. It puts forward that the principles of unity and diversity, theory and Practice, integrity and stage, interdisciplinary integration and diversified development should be followed, and teaching strategies should be given from the construction of theme units, the clarification of teaching objectives, and the creation of teaching situations, so as to improve the teaching quality and cultivate students' comprehensive quality.