The invention discloses tin-titanium composite oxide with a high-proportion 101 crystal face and a preparing method thereof. The preparing method includes the steps that tin salt and titanium salt are used as raw materials and prepared into solutions respectively, and then the solutions are mixed, subjected to heat treatment and heat preservation and dried to obtain the tin-titanium composite oxide. The general formula of the tin-titanium composite oxide is Sn1-xTixO2, wherein 0.1<=x<=4, the tin-titanium composite oxide is in a flake shape, the proportion of the exposed 101 crystal face is 70-90%, the thickness of the flake in the 101 direction is 5-30 nm, and the size of the flake is 50-200 nm. The obtained tin-titanium composite oxide can effectively increase the electron transmission speed and the lithium-ion transmission speed and can be used as a negative material of a lithium-ion battery.