A method for raising parameter quantization accuracy of vocoder fundamental tone cycle includes inputting signal sample point sub-frame at coding end, picking up parameter vectors of fundamental tone and voiced-voiceless sound, quantizing voiced-voiceless sound parameter vector to obtain its quantization index value, carrying out quantization on certain scope to obtain relevant quantization index value being coded and outputted, decoding to obtain united quantization index value, carrying out counter quantization, setting fundamental tone cycle of voiceless sound to be 50 and using set cycle to make voice synthesis.