As one of the most important offshore basins in China, there exist many different kinds of fluid diapirs in the Zhujiangkou Basin, which have been introduced in some papers. However, the systemic study of these diapirs is still to be expected on its classification and origin, which can understand fluid migration better. Fluid diapir structure is a special style of fluid migrating upwards. The aim of this paper is to identify and classify the fluid diapir structure, to analyze the messages implied by the fluid diapir structure, to find out a new method of evaluating the fluid diapir structure characterized by the blank seismic reflection, and to discuss the origin of the diapirs according to basin modeling and structure analysis.