Nowadays in many industries, there are a huge amount of wastewater that mixed with oil particles are produced. Separation of oil particles that emulsified in oily wastewater is the basic challenge nowadays. This article review illustrates some of the conventional and advanced separation techniques that are used for separation. Separation oily wastewater using gravity and skimming, agglomeration, flotation using air, flocculation, and coagulation are all traditional oily wastewater treatment technologies that have some problems such as it is expensive in operation process, also efficiency is very weak and not effective ways, corrosive for air and land, and it leaves pollutant problems but advanced separation techniques such as separation using technology of membranes are concentrated applied for the separation of emulsified oil in wastewater in lately years as ultrafiltration membranes (UF). Generally, because of their ease of processing and low cost, also their high flexibility, polymeric membranes are critical in these processes. Many types of additives are added to a based polymer to increase it is hydrophilicity and increase it is properties as enhancing pure water flux (PWF). Additives added such as inorganic nanoparticles as titanium oxide (Tio2) which enhance flux of pure water but using pure membrane is less in pure water flux. Also adding polymeric additives to a based polymer such as polyvinyl-pyrrolidone (PVP)increase water flux and lower fouling occur. In this article review various types of separation techniques are mentioned and illustrated clearly.