The article considers A.F. Losev's philosophy of music in the context of his entire religious worldview and as the part of his Christian-Neoplatonic philosophy. Synthesizing Pythagorean-Platonic and Romantic musical doctrines, Losev concludes: music is the expression of the life of numbers, a meonic-hyletic element that rages inside numeric constructions. So it is necessary to analyse the concept of number in the system of Neoplatonic thought. In the Neoplatonic hierarchy of the universe both numeric sphere and music are located at the source of all the eidei, above them and between the One (the first hypostasis) and the World Intelligence (the second hypostasis). Then music is considered in the context of the relation between the uncreated Absolute (Tetrade A) and the created world (Tetrade B). Losev's doctrine on the Tetrades A and B (connected not by essence but by energies) is the important modification of Neoplatonism. Finally the article considers Losev's account of music in relation to the absolutized individual person.