On the basis of analyzing the working principle of ECT data acquisition system and wavelet Kalman algorithm, the realization method of a new ECT data acquisition filter is proposed about the acquisition accuracy and real-time requirement of electrical capacitance tomography ECT (Electrical Capacitance Tomography) data acquisition system. The method uses the principle of multiplexing and folding structure to make the multi wavelet decomposition and reconstruction combined, parallelize high-pass filter and low-pass filter to meet the requirement of real-time. The simulation experiment results show that the processing speed of the improved ECT data acquisition filter is improved, the acquisition speed and the accuracy of the data are better than the traditional ECT data acquisition system, it provides a new filter realization method for ECT data acquisition system.