Some methods for deducing circulation from hydrographic data are reviewed. These methods could be classified into three types according to their different dynamics and their different applications as follows:①description methods, the major character is only to qualitatively describe the direction of ocean circulation.②diagnostic methods which combine thermal wind relation with tracer conservation, these methods could be used to quantitatively calculate the absolute ocean geostrophic currents. Some oceanographers began to consider the  ageostrophic current component by these methods, and ③Sarkisyan' s diagnostic methods and the other complicated models. Taking winds, topographic effects into account, these methods quantitatively calculate the absolute currents, which include geostrophic and ageostrophic components. In this paper, we will discuss their progress together with the South China Sea circulation. We will also analyze their developmental trends in the study of deducing ocean circulation from hydrographic data. For studying the SCS circulation, these methods which deduce the ocean circulation from the hydrographic data play a very important role in recognizing the SCS ocean circulation while the differences of the results from these methods in calculating SCS ocean circulation need to be studied further.