For horizontal wells with high water cut, water shutoff operations should be conducted to improve the oil production. But not all the wells with high water cut are suitable for water shutoff. To select the most suitable horizontal well to conduct water shutoff operation, various factors related to well production should be considered. On the analysis of waterflood impact factors, geological parameters and production factors are selected, which have great impact on horizontal well waterflood in building the decision-making system for reservoir with bottom water. Expert system with uncertainty representation method was used for characterizing the filter index. In building the optimized horizontal well water shutoff decision-making model, fuzzy mathematical comprehensive evaluation technology and variable weights evaluation method is used. Using this model, the wells having greater potential to conduct water shutoff operation can be figured out. The case study shows that, in this method all the factors affecting waterflood is considered and negative effect of singular factor on well selection decision-making is avoided, which can make the water shutoff well selection more scientific and logical.