Faulting is essential for the migration and accumulation of oil and gas. However，expanding space of reservoir resulted from a number of cracks being formed with faulting and the prediction of favorable reservoir formed have not been paid enough attention. Based on the basic theories and methods of fractal geometry，the fractal fracture characteristics of the seismic reflection layer T6 in Linnan subsag of Huimin sag，Bohai Bay Basin（middle section of the third member of Shahejie Formation）has been analyzed quantitatively. The relationship between fractal dimension values of fracture and the proved oil and gas reservoirs distribution has been discussed and the favorable reservoir space resulted from faulting has been predicted. The results show that the fault structures in the research area within the measurement section of 0.187 5-1.5 km have good self-similarity and the correlation coefficients are generally above 0.970. The larger the value of fractal dimension，the more complex the fault structure. The fractal dimension value correlates with the fracture development. The favorable reservoir in the middle of the sag distributes within the closed contours ranging from 1.1 to 1.4. The favorable reservoir in the south and the north of the sag distributes within the closed contours above 1.2. The fault structure positions with fractal dimensions between 0.8 and 1.4 in this area are the advantage areas for oil and gas accumulation，and the positions with fractal dimensions above 1.4 are the areas for oil and gas migration. The area，where is west to Well Xia224 and south to Well Xia53 and Well Jiexie201，is predicted to be the favorable crack for hydrocarbon exploration combining with sedimentary features.