Owing to continent -continent collision along the Dabie-Jiaonan orogenic belt between the North China and Yangtze plates, the Yangtze plate south of the orogenic belt became a foreland deformation belt, and a foreland basin along the Yangtze River was developed on the foreland belt.

Transporting conditions of faults required in formation of large and medium gas fields with high efficiency in foreland basin;

Different origins of natural gas in secondary gas pool in Western Sichuan foreland basin;

Overpressure compartment sealed by faults in Kuqa foreland basin;

Based on forland basins evolution,tectonic features,sedimental model,thermal process,reform process and model recovery,the paper analyzes forland basins theories and pays more attention to geological process,evolutional development and sedimental model.

According to the latest researches, there is a set of Mesozoic(T_3-J_(1+2)) palaeo-foreland basin deposits in the deep-seated Songliao Basin, which are composed of detrital rock, coal and volcanic rock.