Introducing instrumental music into the classroom is one of the important contents of the reform of music teaching in primary and secondary schools. I think it must meet the following conditions: first, there must be instruments with uniform tuning to facilitate collective performance; second, It should be cheap and economical; third, it should have good sound quality, and the beautiful tone can arouse students' interest; fourth, it should have low technical requirements and be simple and easy to learn. Among the three instruments: recorder, harmonica, and mouth organ, the recorder is the cheapest and easy to carry. It is an entry-level instrument for learning music, unlike the bamboo flute, which most primary school students cannot play and requires a flute membrane. The recorder can be played by primary school students as soon as it is played, and it is easy to master. As long as the teacher teaches well, primary school students can master it quickly, which will definitely stimulate their interest in learning music. The harmonica is also small in size and easy to carry. The disadvantage is that the sound holes are not intuitive, the bass and treble scales are not arranged in order, and it is difficult to remember the sounds when playing and absorbing them. It is difficult for students to master, but as long as they work hard and practice hard, it is indeed a good thing. It is a very good musical instrument. Not only does it have a beautiful tone, it is also a harmonious instrument that can be used as a soloist, accompaniment, or ensemble. It is suitable for students of all ages. Among these three instruments, I think the mouth organ is the best. It is a keyboard instrument. The keyboard is conducive to learning the basic knowledge of music. The mouth organ has a large volume and beautiful tone. It can play double notes, chords, and modulate. After learning the mouth organ, it is very easy to learn the piano, electronic keyboard, organ, and accordion. There are thirteen-key, twenty-four-key, and thirty-two-key mouth organs. Among them, the thirteen-key one has no black keys and cannot change the key. It is an option for beginners in lower grades.