In modern communication systems, because the signal is often mixed with a variety of complex components, many signal processing and analysis were carried out on filters.However, the conventional digital filter design workload. MATLAB can be quickly and efficiently using digital filter design and simulation. This article describes the basic concepts of IIR digital filters, digital filter design steps introduced to Butterworth filter represented by several common and constant pulse corresponding method and bilinear transformation design, design using MATLAB specific performance digital filter and the results obtained response plan. and analyzed Keywords: IIR digital filters, MATLAB, the same impulse response method and the bilinear invariant method.