Water stress effects on stem diameter variations (SDV) were studied in a pot experiment on cotton (Gossypium hirustumL. Meimian99B). Water restriction was imposed at the flowering stage and were compared with a well-watered controltreatment. The volumetric soil water content (θv) and SDV were monitored continuously. The objective was to determinethe feasibility of using the parameters derived from stem diameter measurements, including maximum daily stem shrinkage(MDS), maximum daily stem diameter (MXSD), and minimum daily stem diameter (MNSD) as indicators of plant waterstress. The different behavior of SDV was founded at different growth stages. At stem-maturing stage, MDS increasedand MNSD decreased in deficit-irrigated plants compared with the control plants, therefore, it appeared that MDS andMNSD ccould be used as available indicators of plant water status. At stem growth stage, there were no significantdifferences in MDS values between treatments but MXSD and MNSD responded sharply to soil water deficits. Thus, forrapidly growing cotton, the course of MXSD or MNSD with time offered a consistent stress indicator. SDV was alsoclosely related to atmospheric factors, solar radiation (Rs) and vapor pressure deficit (VPD) were found to be the predominantfactors affecting MDS, followed by the relative humidity (RH), while air temperature (Ta) and wind velocity had the leasteffect. A good linear relationship was founded (r2 = 0.921) between MDS and environmental variables (Rs, VPD, RH, andθv), which can be used to establish a reference value for detecting plant water stress based on the MDS patterns. Water stress effects on stem diameter variations (SDV) were studied in a pot experiment on cotton (Gossypium hirustum L. Meimian 99B). Water restriction was imposed at the flowering stage and were compared with a well-watered control treatment. The volumetric soil water content (θv ) and SDV were monitored continuously. The objective was to determine the feasibility of using the parameters derived from stem diameter measurements, including maximum daily stem shrinkage (MDS), maximum daily stem diameter (MXSD), and minimum daily stem diameter (MNSD) as indicators of plant waterstress. The different behavior of SDV was founded at different growth stages. At stem-maturing stage, MDS and MNSD decreased in deficit-irrigated plants compared with the control plants, therefore, it has that that MDS andMNSD ccould be used as available indicators of plant water status. At stem growth stage, there were no significant differences in MDS values ​​between treatments but MXSD and MNSD responded shar The course of MXSD or MNSD with time offered a consistent stress indicator. SDV was alsoclosely related to atmospheric factors, solar radiation (Rs) and vapor pressure deficit (VPD) were found to be The predominantfactortric MDS, followed by the relative humidity (RH), while air temperature (Ta) and wind velocity had the leffeffect. A good linear relationship was founded (r2 = 0.921) between MDS and environmental variables (Rs, VPD, RH, and θv), which can be used to establish a reference value for detecting plant water stress based on the MDS patterns.