Monosodium glutamate(MSG),disodium 5'-Inosinate(IMP)and guanosine 5'-monophosphate disodium salt(GMP)are main components that enhance flavour.I+G is composed of 50% IMP and 50% GMP.Study on processing stability of MSG and I+G has food production and processing significance.This experiment mainly used HPLC to measure the content change of monosodium glutamate and I+G which were treated with different sterilization temperature,sterilization time and acidity.The results showed that when sterilization temperature was 85℃,100℃,121℃ for 30 min,monosodium glutamate lost 3.16%,13.21%,30.10% respectively,and I+G lost 8.18%,12.91%,22.97% respectively.When sterilization time was 5min,15min,30minutes at 100℃,monosodium glutamate lost 1.43%,7.25%,8.63% respectively,and I+G lost 6.08%,8.78%,10.12% respectively.When acidity declined from pH 7 to pH 3(pH 7,pH 6,pH 5,pH 4,pH 3) at 100℃ for 15min,monosodium glutamate lost 2.2%,10.30%,22.4%,39.09%,52.50% respectively,and I+G lost 7.59%,9.30%,10.60%,12.89%,26.33% respectively.