Abstract: Combining factual exploration achievements of the old oil—bearing region and employing analogy method and logarithmic normal distribution, this pa per suggests prediction of oil and gas exploration extent and prospect of the Biyang depression.A proposal is provided which uses six parameters of generation, reservoir，cap rock, trap, migration and accumulation to establish 3—D digital geological model of stereodisposition and quantitative evaluation of 3—D space. The proposal is beneficial to better exploration plan and drilling programming—making.