Digital music has various characteristics, such as melody, rhythm, timbre, and harmony. According to these characteristics, music can be classified using artificial intelligence (AI). Music can reduce cognitive dissonance and improve memory in humans; however, occasionally, dissonant music can cause negative effects, such as aggravating depression. Therefore, music can be classified using technical methods and used selectively for human mood regulation, sleep improvement, disease relief, and treatment. Herein we present a survey of the fields of music, AI, and health to shed light on the digitization of music. In this survey, we (1) summarize the various characteristic elements of music, such as melody, rhythm, timbre, and harmony; (2) discuss the role of neural networks in classifying music based on these musical characteristics; (3) summarize the positive and negative effects of music with respect to five areas: sleep, memory, attention, mood, and movement; (4) summarize the therapeutic effect of music intervention with respect to various illnesses; and (5) present the future of music therapy as well as provide a few suggestions with respect to music therapy.