Formulating reasonable water saving goals for different industries in the region can provide a reference for the construction of water saving cities. Based on the decoupling theory, taking Guangdong Province as an example, we systematically analyzed the spatial differences of the decoupling relationship between industrial economic development and water resources utilization in 21 cities during the 13th Five Year Plan period from 2015 to 2017. On this basis, a water saving target calculation model based on the decoupling theory was constructed, and the water saving targets of weak and strong decoupling states for different industries in the 21 cities were calculated. From 2015 to 2017, the decoupling of economic growth and water resources utilization in Guangdong Province was developing steadily, but the economic growth of various industries and water resources utilization were not completely decoupled, and there were significant spatial differences. Among them, the economic growth of the primary industry in the Pearl River Delta failed to decouple from water resources utilization, so as the economic growth of the secondary industry in eastern, western and northern Guangdong. Different industries and different cities have different water saving pressures in the process of decoupling. Among them, the primary industry in Zhuhai City was facing the strongest pressure, which needed to save 15.64%~20.79% water. Whereas the second industry’s water saving pressure was the largest in Zhaoqing City, with a decoupling water saving target of 20.87%. Moreover the third industry was under the strongest pressure in Zhongshan City, which had a target of 3.65%~12.83%. In general, Guangdong Province had achieved the decoupling of overall economic growth and water resources utilization from 2015 to 2017, but the water use efficiency of the industrial economy in some areas still need to be improved. For example, the water consumption level of the primary industry in the Pearl River Delta was relatively low, and in eastern, western and northern Guangdong, the economic growth of the regional secondary industry failed to get rid of the high water consumption mode. The proposed water saving target calculation model based on the decoupling theory can provide a reference for the formulation of regional water saving targets for various industries.