Abstract: AlN thin film was prepared on Si(111) and Si(100) substrates by laser molecular beam epitaxy technique, and the effects of substrate temperature and laser energy on phase structure and morphology of the film were studied. The results show that the low laser energy and high substrate temperature were beneficial to orientation degree and surface quality of the film. AlN film on Si(111) substrate showed the single preferred orientation of h-AlN(002) when laser energy was 100 mJ. The film on Si(100) exhibited small diffraction peak of h-AlN(100) at 600 ℃, and presented weak preferred oritation of h-AlN(002) at 700 ℃. It was easy to grow the AlN film with high orientation degree on Si(111) substrate.