This paper gives the relationship between the superconductive critical temperature and the composition of the alloys in Ti-Pd system, and discusses it in connection with the Ti-Pd phase diagram. It is pointed out that the superconductivity in the Ti-Pd system is due to the contribution of the titanium-palladium solid solution. It is also suggested that the limit of the palladium solubility in Ti-Pd system should be relatively large.