Tensile tests, compression tests and three point bending tests have been conducted on longitudinal and transverse specimens of as-cast full lamellar Ti-46Al-0.5W-0.5Si alloy with columnar grains at room temperature. The fracture surfaces of tensile samples have been investigated to analysis the reason of different mechanical properties. Results show that the alloy exhibits mechanical property anisotropy, the tensile and bending properties of transverse specimens are much better than those of longitudinal specimens, but the compression yield strength is lower. The mechanical properties of the alloy strongly depend on the angle between the loading axis and the lamellar interface, do not depend on the growth direction of columnar grains. When the tensile stress of the transverse specimen is parallel to the lamellar interface, the interface of α2/γ lamellar can effectively block the crack growth, which plays an important role on improving their tensile properties. When the compression stress of the longitudinal specimens is perpendicular to the lamellar interface, the microcracks between lamellae can close up, without any more growing, resulting in obtaining higher compression yield strength.