The compilation of oil production project of oilfield is a huge and complex decisions making process, which involves multi-properties, multi-objectives problems. Considering the fact that the traditionally empirical methods already couldn't meet the requirements such as scientific, advanced, and economic, we divide the decision making problems in oil production project into two categories: predictable decision making and evaluation decision making. Based on the characteristics of these two types of problems, we design the decision supporting system in oil production project of oilfield, which use B/S model, composing by model base, method base, database, and user interface. This system made full use of the history data of oilfield, improved the value of data, and greatly enriched the decision making methods for oil production project compilation. It also made the decisions more reasonable and improved the quality of project.