Abstract: A new group of LPC parameters, LSP, is studied for use in speech analysis and synthesis. Experiments proved that LSP are frequency - domain parameters which can track formants directly and can detect pitch and differentiate voiceless / voiced sounds easily, and at the same time have good stability and distinguished characteristics in interpolation and quantization. A method is given for LSP parameters computation using two - side comparison by spectrum property. It can simplify computation in analysis. It has been reported that LSP coding can maintain the same speech quality as the lattice filter synthesizer, with a 25% bit rate reduction.