In this paper, thermal insulation boards comprising expanded vermiculite and gypsum were manufactured by casting and compression molding methods respectively. The effects of flake size and preparation methods of expanded vermiculite (EV), ratio of calcined gypsum/EV and molding methods on thermal and mechanical properties were discussed. The results indicated that the thermal conductivity (λ) and compressive strength of the boards decreased with the increase of flake size, and increased as the ratio of calcined gypsum/EV rose, and the density of the boards increased linearly with the increasing ratio. Compared to compression molding, casting technique can make insulating materials with higher thermal conductivity, compressive strength, and lower water content. The boards containing EV expanded by microwave chemical method presented a better thermal insulating property (λ=0.091W•m-1•K-1) relative to the ones filled with microwave exfoliated EV (λ=0.107W•m-1•K-1). The prepared materials can be used for heat, acoustical insulation and moisture adjustment.