Abstract: The Hongze sag is located in the northwest of the northern Jiangsu Basin,with some potential for hydrocarbon exploration.Based on the results of basin modeling,it can be concluded as following:a) most of source rocks are low matured and the matured source rocks are only restricted in the deep part of the sag;b) large scale of hydrocarbon generation and accumulation is occurred after sedimentation of Yancheng formation,but a lot of low or nonmatured oil were generated before Wubao and Sanduo movements;c) the deep part of the sag is the main area for hydrocarbon generation and accumulation;and d) distance of oil migration is short.In a word,the Hongze sag is characterized by low matured source rocks,short migration,and limited accumulation.It is necessary to pay more attention to the study of the sag for the sake of success of petroleum exploration in the area.