Liaohe basin, a faulted basin, has lots of faults,which have important influence on oil and gas enrichment , and control migration and accumulation of petroleum. This paper considers that main faults control oil and gas enrichment, and sub-faults play important roles on lateral blockage and redistribution of petroleum, and opening of faults lead to various degrees of petroleum enrichment in various fault blocks. So,the correct understanding of faults has great significance on exploration.