Abstract: The process, microstructure evolution, strengthening mechanism and microstructure characteristics of high-strength low-carbon automobile steel plates (ZJ510L steel) by EAF-CSP technology at Zhujiang Steel of China were studied by optical microscope, TEM and mechanical property tests. It is shown that the microstructure of ZJ510L is refined by increasing the rolling pass and the cooling rate. The size range of final ferrite is about 5-6 μm. Precipitates consist mainly of Al₂O₃, MnS, AlN and lots of carbonide particles, and their size range is about 20-150 nm. It is verified that ZJ510L steel possesses a good combination of strength and plasticity due to its fine microstructure and has excellent formability and notched bar impact strength. Refinement strengthening is the primary strengthening mode.