Two new type criteria of deformation of a single droplet were introduced to estimate the effect of shear flow on deformation by the ratio of long radius to short radius or stretching rate, and they were analyzed and compared through the experiments. The experiments show that the ratio of long radius to short radius and stretching rate grow with the increase of shear velocity and the deformation shrinkage coefficient of a single droplet increases at first and then decreases. Compared with to the theoretical results it deviates greater with emulsifier. The shear stress attained by the stretching rate agrees better with the practical value than that by the ratio of long radius to short radius.