Abstract: Silicon steel thin strips with silicon content of 0.5wt%, 1.0wt%, 3.0wt% and 4.5wt% were prepared by twin-roll continuous casting process, and the microstructure of the strips were observed by means of optical microscopy, and on the basis, the effect of post-treatment process on microstructure and properties of the strips was studied. The results show that the post-treatment process of one-time cold rolling and annealing between 850-950 ℃ was suitable for the strips with silicon content of 0.5wt% and 1.0wt%, but the two-times cold roll and annealing at 950 ℃ was a suitable post-treatment process for the strips with above 3.0wt% silicon. The magnetism properties of the thin strip with silicon content of 3.0wt% and 4.5wt% annealed at 950 ℃ after cold rolling was best, the core loss was about 4.30W·kg-1 and magnetic induction was about 1.68 T.