The northeast subsag in the Laizhouwan sag is characterized by well- developed extensional deformation, strike slip deformation, and contraction deformation during Cenozoic. In order to understand its tectonic attribute and genetic mechanism, the latest drilling and seismic data was used to analyze the spatiotemporal combination relationship between extensional deformation and contraction deformation. The results show that inside the subsag, the extensional deformation and contraction deformation are synchronous and continuous during deformating period, and their deformation displacement is perpendicular to each other. It is the result of the continuous action of the stretching vector component and the compression vector component during the right strike slip activity of the Tanlu fault. In terms of genetic mechanism, the northeast subsag was formed by the strike- slipping forces of the Tanlu fault zone, which became dextral strike- slipping since the E2s3M was deposited. The area where the northeast subsag located was a part of the Laibei low uplift before the E2s3M was deposited, after which it sank and merged into the Laizhouwan sag. Although both belong to the Laizhouwan sag, the attribute of the northeast subsag and the southern main subsag are different: the northeast subsag is generated by dextral strike- slipping since the E2s 3M was deposited, while the main subsag is an aearly Paleogene half graben reformed by dextral strike- slipping later.