The invention relates to the field of energy and power, and discloses a combustion chamber combustion oscillation control device and a combustion chamber combustion oscillation control method. The combustion chamber combustion oscillation control device comprises a conical transition structure, an air inlet cases and a flame barrel, wherein the conical transition structure, the air inlet case andthe flame barrel are coaxially arranged; the tube diameter of the flame barrel is larger than the diameter of the air inlet case, the diameter of the air inlet end of the flame barrel is communicatedwith the large-diameter end of the conical transition structure, and the small-diameter end of the conical transition structure is communicated with the air outlet end of the air inlet case; and the inner wall of the conical transition structure is attached to the frontal surface of flame and along the direction of flame flow. According to flame angles in a natural state, the combustion chamber combustion oscillation control device can change the shape of the flame barrel limiting region and eliminate corner vortex areas of the flame barrel so that the influence of a large-scale vortex structure on the flame can be reduced, movement of the flame is limited, and finally an effect of inhibiting the combustion oscillation is achieved; and practice shows that the combustion chamber combustionoscillation control device has remarkable effects on single-swirl flame, layered rotational flow flame and the like, thereby having relatively good universality.