The invention relates to a ternary alloy for improving the titanium alloy ingredient homogeneity and a preparing method and application of the ternary alloy. A ternary intermediate alloy for improving the TC11 titanium alloy ingredient homogeneity is provided, and is basically composed of 5%-6% of Si, 55%-60% of Mo and the balance Al. Meanwhile, a preparing method and application of the ternary intermediate alloy are further provided. The ternary intermediate alloy is suitable for serving as a raw material of a high-strength high-temperature titanium alloy TC11; compared with other ternary alloys, the weight percentage of the Si is improved, the ingredient scope of the high-melting-point element Mo is shrunk, and therefore the smelting process of the ternary alloy is controllable, smelted cast condition blocks are better in crushing performance, powder-like products with the granularity smaller than or equal to 1 mm can be obtained, the ingredient homogeneity of the main elements including Si, Mo and Al in the TC11 alloy can be effectively improved, the probability that the high-melting-point element Mo forms high density inclusion segregation defects in the cast ingot smelting process is reduced, and the ingredient homogeneity of TC11 titanium alloy cast ingots and titanium materials is guaranteed.