In view of some problems such as the complex calculating process, large deviation compared with ideal pink noise on the existing generation methods of pink noise, this paper puts forward a new generating method of pink noise using Auto-regressive moving average (ARMA) model; First, constructing an ARMA model of undetermined coefficients, and deriving the formula by Z transform and power spectrum estimation; Second, using the known pink noise analog filter transfer function H(s) and the principle of bilinear Z transformation method to derive IIR digital filter transfer function H(z), and then the ARMA model of pink noise can be obtained; Finally, using MATLAB to do its power spectrum estimation and comparing with the ideal pink noise. As the MATLAB simulation results shown, this method has a higher fitting degree with ideal pink noise and complies with the performance requirements of pink noise.