At primary school, especially in Grade 4, integrating environmental education into Science subject not only helps students form correct awareness of the environment but also develop their ability to apply knowledge to protect and improve the surrounding environment. This article proposes a process of integrating environmental education in teaching Science subject in Grade 4 towards developing cognitive and knowledge-application competencies on environmental protection. Then, the process was applied to design activities to integrate environmental education in teaching the topics “Substances” and “Plants and animals”.At primary school, especially in Grade 4, integrating environmental education into Science subject not only helps students form correct awareness of the environment but also develop their ability to apply knowledge to protect and improve the surrounding environment. This article proposes a process of integrating environmental education in teaching Science subject in Grade 4 towards developing cognitive and knowledge-application competencies on environmental protection. Then, the process was applied to design activities to integrate environmental education in teaching the topics “Substances” and “Plants and animals”.