The invention relates to yoghourt, in particular to long-shelf-life 
pasteurization yoghourt and a preparation method thereof, which are characterized in that after milk pretreatment is carried out, a mixture of 
colloid and 
sugar (with the weight ratio of the 
colloid to the 
sugar of 1 / (0 to 100)) is added into the milk, then, obtained materials are homogenized, the 
pasteurization is carried out, after the obtained materials are cooled, strains are added into the obtained materials for 
fermentation, and the filling is carried out after the sterilization to obtain the products of the invention, wherein the milk can be 
fresh milk or reconstituted milk, wherein the 
colloid addition has the weight part proportion of milk / colloid=(95 to 99.9) / (0.1 to 5), wherein the colloid has the ingredients and the weight part proportion of 
starch / agaragar / glutin=(0.5 to 90) / (0.1 to 15) / (1 to 40). The colloid used in the method of the invention carries out experiments for many times by the inventor. After the colloid of the invention is adopted, the texture of the yoghourt can be protected from generating synaeresis after the 
pasteurization. Products prepared by adopting the method of the invention have the 
shelf life about half a year.