According to the derivation of the DTF Goertzel, algorithm can be regarded as a zero state response of the two order IIR filter. In order to solve the dependence on special decoding chip of signal detection, it can be combined the IIR filter with the Goertzel algorithm to improve the accuracy and stability of DTMF signal detection. Goertzel sequence respectively through by IIR filter and universal filter, then compare the two outputs. The results show that the combination of IIR filter and the Goertzel contribute to improve the accuracy and stability of DTMF signal detection. Through the simulation of Matlab, it can be concluded that the Goertzel with IIR filter is transplanted to the DSP hardware can solve the dependence on special decoder chip.