The degree of water stress is an important life index for characterizing plant health. In addition, water stress is a reliable foundation of plant precise tending technology system. Therefore, to study the realtime detecting method of water stress for plants has important theoretical significance and practical application value. The research progress of detecting methods of water stress was discussed from two aspects of physiological indexes(stem flow, water potential, transpiration rate, stem water content) and morphology(2D image, 3D image, stem diameter, spectral feature). The detecting theory of each method was also expounded. Compared with each other, advantages and disadvantages of each method were analyzed from the point of practical application. Detecting methods based on physiological indexes had higher measuring precision. But it had complex operation progress and varying degree of destruction to plants. Detecting methods based on morphology had advantages of nondestructive, quick and simple operation. But it had relatively larger measuring error. Some international production organizations and its relative products which had been widely recognized for detecting water stress were also recommended to researchers. Eventually, two research focuses were proposed based on each methods advantages and disadvantages.