Aiming at the development bottleneck of high strength and high toughness titanium alloy, from the perspective of classification applications, and based on existing research of extra-high strength and high toughness titanium alloy. A new type of metastable β titanium alloy was designed by selecting the types and weights of alloying elements by Mo equivalent, combined with the design of the structure. After processing and testing of ingots of laboratory and pilot scale specifications, under optimized forging and heat treatment processes, the alloy can stably reach two strength levels. One is that the strength is greater than 1500 MPa, the elongation is greater than 5%, and the fracture toughness is greater than 45 MPa·m1/2; the other is that the strength is greater than 1300 MPa, the elongation is greater than 6%, and the fracture toughness is greater than 60 MPa·m1/2. In comparison with the existing high strength and high toughness titanium alloys, it is evident superiority of the new alloy for any performance levels.