The present invention discloses a switching amplifier and its modulations process, which belongs to the field of non-filters-type switching amplifier. The switching amplifier comprises: pulse-width modulation with dual comparator, multiple-loop feedback structure, only one integrating amplifier with dual-ends output needed for each loop, no less than two feedback loops set between the integrating amplifier and H-bridge, in addition, no any low-pass filters needed adding to the feedback path. Multiple feedback loops are adopted in the present invention, which can low the distortion of the switching amplifier to the extent. Furthermore, no any extra low-pass filters are needed adding to the feedback path, which making the products a higher cost effectiveness.