This study designs music courses to cultivate children's sense of rhythm based on the three main forms of Orff music teaching system (language, movement and percussion). This paper aims to explore the development level of children's sense of rhythm in large classes and the influence of Orff music teaching activities on the cultivation of children's sense of rhythm in large classes, and puts forward specific teaching suggestions according to the experimental results, so as to provide a reference for kindergarten to carry out better music teaching activities. This research adopts the experimental study, two large selection of tianjin a kindergarten children as experimental object, it can be divided into the experimental group and control group, experimental group children using orff music teaching method, the control group on the music of traditional single teaching young children, through a pretest to ensure two groups of young children's sense of rhythm, there is no significant difference of development level has the homogeneity, On this basis, the teaching experiment of different teaching methods is carried out. After the experiment, the post-test is carried out through the observation record table of children's sense of rhythm, and the difference in the development of children's sense of rhythm is compared between the two groups. So as to analyze. The experimental results show that: 5-6 years old children can master the basic rhythm type; Orff music teaching method has a good promotion effect on the cultivation of rhythm sense of children in large classes, and is better than the traditional single music teaching. Kindergartens should provide a convenient environment for children's music education and pay attention to improving teachers' educational concepts. Meanwhile, teachers should constantly enrich themselves and improve their professional qualities.