Abstract: In order to study the properties of transglutaminase prepared in the laboratory, two different addition techniques of TGase were compared. One was to add fermentation agent after crosslinking milk by TGase following inactivation TGase by heat treatment, the other was to add TGase and fermentation agent to milk at the same time. These adding conditions of TGase were determined by comparing the two kinds of yogurt and control samples (without TGase) . Fermentation time, texture changes, whey precipitation and sensory evaluation of yogurt were compared. Results showed that the firmness, viscosity, whey precipitation and sensory evaluation of the yogurt crosslinked by the active TGase were greatly improved, and the optimum adding amount of TGase was 30U/L.