Abstract: When divers work in deep sea,they must breathe helium-oxygen mixture in stead of air.Since the vocal tract is adapted to produce speech in normal atmosphere,a changed compo-sition of breath mixture causes distortions in the speech.Line-spectrum pair(LSP) associated with speech spectrum leads to synthesis filter based on LSP will never degrade system steady-state performance.Moreover LSP are important parameters of vocal track model in speech coding.Their quantization is closely related to synthetic speech quality.An LSP-based algorithm for helium speech enhancement is proposed in this paper.Having analyzed the resulting data,we find the universal LSP coefficient in the new algorithm.By comparison with the LPC method,it is seen that the pro-posed algorithm can correct helium speech leading to significant enhancement of intelligibility.