The perovskite layer is the most crucial factor for the high performance tin-based perovskite. Herein, we investigate the effect of solvent on the morphology of perovskite films systematically. Dimethyl sulfoxide (DMSO) has been adopted as a high boiling point combined with the commonly used N,N-dimethylformamide (DMF) to control the rapid nucleation and retarding crystal growth. A pinhole-free MASnI(3) perovskite film with dense and large grains is obtained. By optimizing the solvent composition, multiple tin-based mixed iodine and bromine perovskite solar cells (MASn(I1-xBrx)(3) 0 <= x <= 1) were fabricated. The best photoconversion cell efficiency was obtained at x = 0.67, which yields to 3.20% compared to the original MASnI(3) (1.17%) due to the benefit band level alignment. The conductivity and the stability of the MASn(I1-xBrx)(3) perovskite device was carefully studied.