The invention provides an implementation method and system of a digital filter circuit. The method comprises the following steps: acquiring a filter coefficient; expressing the filter coefficient by adopting a CSD code to obtain a CSD coefficient; according to the CSD coefficients, generating a CSD matrix, wherein each CSD coefficient independently serves as an element of a row in the CSD matrix;extracting a row common item and a column common item in the CSD matrix; respectively counting the occurrence frequency of different row common items and different column common items; determining anoptimal row common item and an optimal column common item according to the occurrence frequency of different row common items and different column common items; decomposing the CSD matrix according tothe optimal row common item and the optimal column common item; and under the condition that the decomposed CSD matrix belongs to a threshold matrix, taking the decomposed CSD matrix as an optimal coefficient matrix, so that the digital filter performs filtering processing according to the optimal coefficient matrix. The use frequency of the adder resource by the digital filter can be reduced, and the space occupied area of the digital filter is reduced.