Abstract: The effect on quality of grass carp muscle irradiated through different doses of 60Co-γ ray was studied. The total number of bacteria declined in index mode with increasing dosage of irradiation. Meanwhile，the moisture content declined significantly （p<0.05） with increasing dosage of irradiation. However，the dosage of irradiation had no visible effect on contents of protein，fat，carbohydrate and ash. There was no significant difference in SFA and USFA contents between irradiated ones and non-irradiated ones. TVB-N value of grass carp muscle could remain the first fresh degree under irradiation of 0kGy or 2kGy，whereas TVB-N value of irradiated ones by 4-10kGy dropped to the second fresh degree. As the irradiation dosage increased，TBA value increased，the‘irradiation flavor’aggravated，and the color of muscle developed into dark red，as well as the texture became unsmooth. In conclusion，the irradiation below 8kGy influenced hardly quality of grass crap muscle.