This experiment was developed with Trehalose and fresh milk as the main raw materials. Mixture of Lactobacillus bulgaricus and Streptococcus thermophilus was used as starter cultures to prepare trehalose functional yoghurt. The optimum formulation and technological parameters were determined by sensory and acid viscosity, the addition of trehalose, the amount of sucrose, the inoculum size and the time of fermentation. The volatile flavor compounds in the whole yoghurt were determined by solid-phase microextraction and GC-MS. The results showed that the optimum formula of trehalose yogurt with the best the taste after fermentation at 42 ℃ for 4 h was 5% trehalose, 4% sucrose, 4% inoculum. In addition, results from gas chromatography mass spectrometry under optimum conditions showed that the contents of ketones and aromatic heterocyclic compounds and other flavor substances in trehalose yogurt were higher than those of sucrose yoghurt. The texture parameters of these two kinds of yogurt were compared. They had little differences in hardness, cohesion and elasticity, and their adhesiveness and chewiness.