Accurate measurement of oilwater interface in the crude oil tank is a basic requirement of petroleum exploitation process. The development of this technology is very important in the research of petrochemical process system engineering. Firstly, 15 kinds of oilwater interface measurement technologies are analyzed. The measurement principle and application of each measurement technology are introduced. These oilwater interface measurement technologies are compared in three terms, including technical mode, measurement mode and calculation mode. Then, this paper focuses on the oilwater interface calculation mode and compares the research progress of algorithms adopted in this direction. The calculation methods are summarized in four aspects, including direct reading method, keyparameter based method, matrixdata based method and imageanalysis based method. Finally, this paper prospects the future development of oilwater interface measurement technology. The future development and the related difficulties are analyzed in five aspects, including hybridmode technology, high precision measurement processing, noncontact measurement, multidimensional data calculation method and intelligent information system construction platform.