This paper presents a parametric matching and smoothing method that is applied to a sinusoidal representation and auditory model-based speech analysis/synthesis system. A 2.6kbps speech-coding algorithm is finally derived based on the speech analysis/synthesis system. The synthetic speech is almost same as that of 3.25kbps speech coding algorithm with overlapping and adding method. A linear interpolation method is utilized to smooth the amplitude parameters, and a nonlinear polynomial interpolation method is used to smooth the frequency and phase parameters. The experimental results demonstrate that the parametric matching and smoothing method can reduce the bit-rate with the speech quality unchanged when it is applied to the sinusoidal representation and auditory model-based speech-coding algorithm.