Calculating the amount of industrial water use is an important task for China to implement the strictest water resources management system. In order to use the existing results of water statistics to calculate the amount of industrial water use, the forecasting methods based on the historical data and the statistical methods combining with sampling are employed to calculate the amount of industrial water use, and then a calculating method is proposed, which is based on the measurements combining with sampling and checked by the trend extrapolation method. The results show that the relative error of the predicted value is less than 10% for the industrial water use scale more than 100 thousand m³through full sampling measurements and that less than 100 thousand m³ through proportional sampling. For the provinces with low technology and insufficient statistics, the census data of water resources in 2011 and other historical data can be used, and the original data should be modified by the trend extrapolation method.