With the acceleration of exploration speed and the upgrade of environment protect requirement，the disposement and use of the oily sludge has become an urgent problem for every oilfield and petroleum company. In this article，the present situation about domestic and foreign oily sludge treatment technology was summarized，such as solvent extraction，chemical cleaning，conditioning-mechanical separation，pyrolysis，ultrasonic，microwave，reinjection/profile，electrokinetic and freeze/thaw. In addition，a comparative analysis of the flow features and process is then undertaken with each of these treatments. What’s more，combined with the actual situation，the current situation and development of oily sludge treatment in Yanchang oilfield were analyzed.