Grey associative analysis in trap assessment is to study the simularity between actural traps and ideal traps; give pool-forming factors different weights through correlation analysis so as to quantitatively evaluate trap's pool-forming condition. The assessment results of the traps on southwest margin of Jianghan Basin indicate that

Xiefengqiao structure is most favourable for hydrocarbon exploration; Nangang 1～3 and Caixue fault-noses and Dingjiahu fault-block are secondary. Caixue and Dingjiahu structures should be major exploration targets in future.