This paper proposes a novel adaptive approach for sigmadelta modulators to significantly improve the dynamic range. Based on adjusting the signal power gain (SPG) of SDM, many dynamic-range (DR) curves can be obtained. A systematic approach with the proposed algorithm has been used to acquire the boundary constraints. Therefore, the wide dynamic range can be achieved without changing the original architecture and increasing the amount of hardware. A fourth order cascade of resonators with distributed feedback (CRFB) structure has been adopted to demonstrate the proposed method. This proposed method can be easily implemented by switched-capacitor circuits. The simulation results show that our work can really improve the dynamic range very well.