Considering the fact that hoarse speech is usually caused by pathological changes of vocal cords, and its motion state is reflected by glottal waveform, we present a new method of research on hoarse speech based on dissymmetric four-mass model of vocal cords and glottal wave analysis-synthesis ill this paper. By linking hoarse speech waveform with glottal wave and the vocal cord model, the characteristic parameters of normal speech and hoarse speech before and after laryngeal operation are studied. The parameters of glottal wave periodicity and vocal cord symmetry of hoarse speech are compared with those of normal speech. It is applied to analyzing the relations between model parameters and hoarse mechanism in pathology and physiology. Experimental results show that this new method can unveil the relations between acoustic features and pathological causes of hoarse speech, providing theoretical and experimental bases both for diagnosing laryngeal diseases non-contactly and for improving the tone quality of hoarse speech. Considering the fact that hoarse speech is usually caused by pathological changes of vocal cords, and its motion state is reflected by glottal waveform, we present a new method of research on hoarse speech based on dissymmetric four-mass model of vocal cords and glottal wave analysis -synthesis ill this paper. By linking hoarse speech waveform with glottal wave and the vocal cord model, the characteristic parameters of normal speech and hoarse speech before and after laryngeal operation are studied. The parameters of glottal wave periodicity and vocal cord symmetry of hoarse speech are compared with those of normal speech. It is applied to analyzing the relations between model parameters and hoarse mechanism in pathology and physiology. Experimental results show that this new method can unveil the relations between acoustic features and pathological causes of hoarse speech, providing theoretical and experimental bases both for diagnosed laryngeal diseases non-contactly and for improvin g the tone quality of hoarse speech.