With the improving of reservoir development level, reservoir geologic research urgently need some new and practical technical methods to describe reservoir more accurately and meticulous. The three-dimensional geological modeling exactly is one of the main aspects to resolve the problem. Take the Chang109 block of Changchunling oilfield for an example. Using Petrel, which is multi-disciplinary and synthetical software for researching reservoir and to establish a 3D geological model as the outstanding characteristic, to build the reservoir model displaying geological information system. That, including the structure model, the sedimentary facies model and the property model, will provide reliable basis potential finding and well placement.