Abstract: The agar as the research object was tested G″ and G′ by frequency scanning method,then was researched how it effected on the stability of drinking yoghurt.The results demonstrated that adding agar could remarkably increase the samples' G′/G″,specifically,0.08% agar addition of sample had a wider range(0~10 Hz)of elastic character than the other samples that had the narrow ranges 0 ~2 Hz. Different amounts of agar addition had the ordinal consistency of trends of G′ and G″,from strong to weak,being 0.16%>0.12%>0.08%>0.04% >0.00%. Stay results of samples were the same as the results of precipitation rates,the sample states became better and precipitation rates got less when the amounts of agar addition increased gradually,and0.08% agar addition was the best volume that made the sample get the most optimal stability,then sample states became worse and precipitation rates got more when the amounts of agar addition reached gradually to the limited level. In conclusion,adding the appropriate amount of agar into the drink yoghurt will perfectly stabilize the whole system,when the addition of the agar was more or less than this suitable amount,the system will be unstable.