Polycrystalline bulk samples of BaSn1-xMnxO3 with x=0, 0.05, 0.10 and 0.13 are prepared by the conventional solid state reaction method. The effects of Mn concentration on crystal structural, optical and magnetic properties of BaSn1-xMnxO3 are investigated systematically. Powder X-ray diffraction (XRD) shows that each of these compounds presens a perovskite structure (with the space group Pm3m) without the secondary crystalline phase. The Mn ions take the Sn sites which is revealed by the XRD, diffusion reflectance spectrum (DRS) and Raman scattering. With the increase of doping level x, the optical absorption edge shifts towards higher wavelength and is smoothened gradually, meanwhile the Raman spectrum shows that Raman mode is also changed. The photoluminescence spectrum under magnetic field shows that near-infrared luminescence is probably related to Sn ions. The magnetization measurement demonstrates that Mn-doped BaSnO3 system exhibits ferromagnetism at low temperature, which can be explained by the F-center exchange (FCE) mechanism.