The invention discloses a regular-hexagon honeycomb core with detachable circular noise-reducing structures. The regular-hexagon honeycomb core comprises regular-hexagon honeycomb main structures, circular honeycomb structures and Y-shaped aluminum components, wherein the circular honeycomb structures are added among the regular-hexagon honeycomb main structures; part of wall plates at the positions, where the circular honeycomb structures and the Y-shaped aluminum components are mounted, of the regular-hexagon honeycomb main structures are lacking; the extra spaces are suitable for the mounting of the detachable circular honeycomb structures; the radiuses, the heights and the mounting density of the circular honeycomb structures can be adjusted as required; once one circular honeycomb structure is not needed, the circular honeycomb structure can be replaced by one Y-shaped aluminum component; not only the regular-hexagon honeycomb main structures and the circular honeycomb structures but also the regular-hexagon honeycomb main structures and the Y-shaped aluminum components can be fastened by adopting the mutually active force generated from material plasticity deformation; and accordingly, the Y-shaped aluminum components can also be detached.