As a newly developed near β titanium alloy, knowledge on heat treatment associated microstructural evolution and its influence on mechanical properties has not yet been established for Ti-7333. Thus mechanical property potential of this alloy is not fully explored. In view of such a situation, a detailed study on heat treatment dependent mechanical property evolution and its correlation with microstructure was made in the present work with an aim to explore the optimum strength–ductility combination. The results show that the optimal combination of strength and ductility of Ti-7333 is realized with a mixed microstructure possessing globular/ellipsoidal αp (about 3% in volume fraction and about 1 μm in average particle size) and fine lenticular/acicular αs (about 30 nm in width and about 500 nm in length) distributed dispersedly in the β matrix (about several microns in average grain size). With such a microstructure, an ultrahigh tensile strength (over 1400 MPa) with a reasonable ductility (over 10% in elongation) can be achieved. The corresponding heat treatment procedure is composed of a subtransus solution treatment at 820 °C for 50 min with air cooling plus an aging at 520 °C/540 °C for 6 h with air cooling. Compared with some other high strength Ti alloys (Ti-5553, Ti-1023, VT22, etc.), the newly developed Ti-7333 exhibits not only a more excellent strength–ductility combination but a more flexible heat treatment operation, rendering it more competitive. The results of the present work provide practical information for process optimization and to enrich the database of Ti alloys.