Objective:To investigate the characteristics of acoustic parameters and spectrograph of functional dysphonia(FD) and the effect of visual-hearing biofeedback voice therapy,to evaluate the value of acoustic analysis technique by computer in diagnosis and voice therapy of FD. Methods:The voice signals of sustained vowel “-琢” were measured with a microcomputer in 68 patients with functional dysphonia and 50 healthy adults. The acoustic parameters(jitter,shimmer,NNE) and spectrographic characteristic were analyzed and compared. The patients were trained by visual-hearing biofeedback voice therapy with the same microcomputer and the effect were evaluated. Results:In 68 cases with functional dysphonia, the shimmer and NNE were significantly increased and the jitter was slightly increased. The spectrograph showed pathologic changes of harmonic waves and formants in middle and high frequencies. The normal acoustic characteristics could be found in 75%(51/68) of the patients with functional dysphonia. 86%(59/68) of the patients with functional dysphonia could pronounced correctly after voice therapy in the first visit. Conclusion:The acoustic analysis by computer technique is useful in the diagnosis of functional dysphonia. The visual-hearing voice therapy by the microcomputer is simple,direct-viewing and effective.