The different chemical composition of silicon and manganese as well as different re-tained austenite fraction ranged from 4% to 10% of the high strength and high elon-gation steels were studied in the paper. The dislocations and carbon concentrationin retained austenite were observed by a transmission electron microscope and anelectric probe analyzer, respectively. The experimental results showed that silicon andmanganese are two fundamental alloying elements to stabilize austenite effectively butretaining austenite in different mechanisms. Meanwhile, the cooling processing playedan important role in controlling the fraction of retained austenite of the hot-rolledhigh strength and high plasticity steels.