Abstract: A multifunction continuous annealing simulator (Multipas) was employed to numerically simulate the continuous annealing process for a low silicon HSLA steel sheet of 380 MPa grade in yield strength. The effects of annealing process on the microstructure and mechanical properties of low silicon HSLA steel were studied at annealing temperatures of 820, 800, and 780℃; and annealing speeds of 60, 120, and 160 m·min^-1. The result indicates that the grain sizes of microstructure are similar at different annealing temperatures and different annealing speeds. The higher strength of low silicon HSLA steel can be gained when it is annealed at a lower annealing temperature and a higher annealing speed. The annealing speed affects the mechanical properties more significantly when the annealing temperature is in a higher level.