Ti-8.15Si alloy was prepared by cold wall induction furnace melting and metal mould casting. The solidification structure characteristics, effects of annealing on the microstructure and the compressive property for the Ti-8.15Si alloy were investigated by OM, XRD, SEM and a multifunctional testing machine. Results show that the Ti-8.15Si alloy presents a eutectic structure composed of αTi and Ti5Si3 compound. The primary Ti5Si3 phases are coarse rod-like, while the eutectic Ti5Si3 phases are finer and dendritic or rod-like, and the cross section is hexagonal. After annealing at 1323 K for 60 min, the coarse rod-like Ti5Si3 phases become small obviously and the dendritic Ti5Si3 phases become discontinuous and fine grains, thus improving the compressive property. As for 120 min, Ti5Si3 grow gradually and a few bulk Ti3Si appears. As for 180 min, more Ti3Si phases are formed and the hardness and the compressive strength increase but the ductility decreases.