As an essential working parameter in crude oil exploitation, the dynamic liquid level depth of oil well is also the indispensable basis for the reasonable arrangement of oil exploitation. In this article, the optimization method based on noise excitation is proposed to ameliorate the existing acoustic resonance method, which has insufficient measurement range and low measurement accuracy. Firstly, the effect of various excitation frequency bands on the measurement results is investigated, and the mathematical model of the output response signal of the system with strong noise excitation is formulated. Then, the extraction algorithm of resonance signal is proposed, which is based on the established mathematical model. The power spectrum estimation and the adaptive homomorphic filtering are applied to suppress the interference of strong noise. Finally, the discrete spectrum correction algorithm based on bilinear interpolation is studied. The resonance characteristic parameters can be estimated accurately. Experimental results show that the resonance characteristic can be extracted under strong noise. The stable measurement of dynamic liquid level can be achieved, where the length of liquid level was over 1 700 m and fluctuation was less than 2 m.