Abstract: This paper studied the effect of propylene glycol alginate and pectin stabilization system on the stability and quality of drinking mulberry yoghurt. Based on the centrifugation sedimentation rate, particle size distribution, viscosity, Zeta potential, Lumisizer stability scan, and Turbiscan results of the mulberry yogurt, and combined with appearance and taste comparison of the mulberry yogurt, the pectin and PGA optimum combination that maintain the stability and taste of the mulberry yogurt are determined. The results showed that: Pectin played a major role in the stability of mulberry yoghurt. PGA had a good effect on water separation, whey separation and water retention of mulberry yoghurt. When the addition of pectin was 0.45% and PGA was 0.1%, the sensory evaluation of mulberry yoghurt was good, and the results were the best, the centrifugal sedimentation rate was only 0.12% and the particle size was only 0.731μm, Zeta potential absolute value was up to 34.95 mV, viscosity was 20.28 cP. Moreover, the storage modulus of mulberry yoghurt in this scheme was moderate, and the results of Lumisizer stability scanning and Turbiscan scanning were also the best. It could be seen that: The stable system constructed by the reasonable combination of PGA and pectin had a significant effect on improving the overall stability of drinking mulberry yogurt under UHT sterilization, improving the texture and taste of drinking mulberry yogurt, and improving the overall quality of drinking mulberry yogurt.