Strong typhoon and earthquake seriously threaten the safety of the life and property of the people. A cost-effective and reliable method is proposed to monitor the natural frequency response of building under excitation of external forces based on the applying digital image correlation method, DIC. The analysis accuracy of this dynamic DIC method is tested and verified by comparing with numerical analysis program, accelerometers, ACC and fast Fourier Transform, FFT. The test results reveal that the analysis accuracy of this DIC method near to the ACC and FFT traditional experimental methods. They demonstrate that using this DIC method to detect dynamic response of building under the excitation of external force has high practicability.