A magnetic circuit for coaxial speaker includes a first magnetic unit, at least one second magnetic unit arranged around the first magnetic unit and at least one third magnetic unit arranged around the at least one second magnetic unit. The magnetic pole arrangement of the second magnetic unit is reversed to the magnetic pole arrangement of the first magnetic unit and the third magnetic unit, enabling a first magnetic loop to be established between the first magnetic unit and the at least one second magnetic unit and a second magnetic loop to be established between the at least one second magnetic unit and the at least one third magnetic unit. The magnetic circuit is practical for use in the inner and outer drivers of a coaxial speaker, providing uniform magnetic field distribution, and facilitating speaker miniaturization.