Abstract: AlSi10Mg aluminum alloy thin sheets with thickness of 0.1-0.8 mm and hollow sheets with inner cavity gap of 0.5 mm were prepared by selective laser melting (SLM) technique. The feasibility of thin-walled structure SLM forming and mechanical properties of the formed parts were studied. The results show that the SLM technique could form thin sheets with wall thickness of more than 0.2 mm and hollow sheets with a cavity gap of 0.5 mm, but there was a hollow in the sheets with thickness of 0.5, 0.6 mm. The precision of SLM formed sheets was further improved by reducing the spot size and adjusting the contour process parameters, and the hollow thin sheet was avoided. The tensile strength of SLM formed and T6 heat-treated thin sheets were both over 200 MPa, and the specimen with thickness of 0.7 mm showed better mechanical properties. Adopting the test SLM process parameters could print thin-walled, closed-cavity radiator products successfully.