The invention discloses a titanium cathode active substance, a preparation method thereof and a titanium lithium ion power battery, and aims to solve the technical problem of enhancing the rate performance of a lithium ion power battery. The formula of the titanium cathode active substance is Li4Ti5O12 / Mx, wherein Li4Ti5O12 is spinel lithium titanate, M is a dopant such as a metal simple substance, a metal compound, a nonmetallic simple substance or a nonmetallic compound; the elements or the ions contained in the dopant enter the Li4Ti5O12 crystal lattice or are compounded with the Li4Ti5O12 crystal lattice; and the preparation method comprises the following steps: the precursor mixture of compound lithium titanate is prepared, and spray drying and heat treatment are performed. The cathode of the titanium lithium ion power battery adopts Li4Ti5O12 / Mx. Compared with the prior art, the titanium cathode active substance has the advantages of high capacity, high bulk density, high volume specific capacity, good high-rate performance, good product uniformity, good battery processability, low possibility of air bulking of the battery, and low cost.